Package 'lintr'

Description

Check that no absolute paths are used (e.g. "/var", "C:\System", "~/docs").

Usage

absolute_path_linter(lax = TRUE)

Arguments

Tags

best_practices, configurable, robustness

See Also

• linters for a complete list of linters available in lintr.

• nonportable_path_linter()

Examples

# will produce lints
lint(
  text = 'R"--[/blah/file.txt]--"',
  linters = absolute_path_linter()
)

# okay
lint(
  text = 'R"(./blah)"',
  linters = absolute_path_linter()
)

Description

Create a linter configuration based on all available linters

Usage

all_linters(..., packages = "lintr")

Arguments

See Also

• linters_with_defaults for basing off lintr's set of default linters.

• linters_with_tags for basing off tags attached to linters, possibly across multiple packages.

• available_linters to get a data frame of available linters.

• linters for a complete list of linters available in lintr.

Examples

names(all_linters())

Description

Lists of function names and operators for undesirable_function_linter() and undesirable_operator_linter(). There is a list for the default elements and another that contains all available elements. Use modify_defaults() to produce a custom list.

Usage

all_undesirable_functions

default_undesirable_functions

all_undesirable_operators

default_undesirable_operators

Format

A named list of character strings.

Details

The following functions are sometimes regarded as undesirable:

• .libPaths() As an alternative, use withr::with_libpaths() for a temporary change instead of permanently modifying the library location.

• attach() As an alternative, use roxygen2's @importFrom statement in packages, or :: in scripts. attach() modifies the global search path.

• browser() As an alternative, remove this likely leftover from debugging. It pauses execution when run.

• debug() As an alternative, remove this likely leftover from debugging. It traps a function and causes execution to pause when that function is run.

• debugcall() As an alternative, remove this likely leftover from debugging. It traps a function and causes execution to pause when that function is run.

• debugonce() As an alternative, remove this likely leftover from debugging. It traps a function and causes execution to pause when that function is run.

• detach() As an alternative, avoid modifying the global search path. Detaching environments from the search path is rarely necessary in production code.

• library() As an alternative, use roxygen2's @importFrom statement in packages and :: in scripts, instead of modifying the global search path.

• mapply() As an alternative, use Map() to guarantee a list is returned and simplify accordingly.

• options() As an alternative, use withr::with_options() for a temporary change instead of permanently modifying the session options.

• par() As an alternative, use withr::with_par() for a temporary change instead of permanently modifying the graphics device parameters.

• require() As an alternative, use roxygen2's @importFrom statement in packages and library() or :: in scripts, instead of modifying the global search path.

• sapply() As an alternative, use vapply() with an appropriate FUN.VALUE= argument to obtain type-stable simplification.

• setwd() As an alternative, use withr::with_dir() for a temporary change instead of modifying the global working directory.

• sink() As an alternative, use withr::with_sink() for a temporary redirection instead of permanently redirecting output.

• source() As an alternative, manage dependencies through packages. source() loads code into the global environment unless local = TRUE is used, which can cause hard-to-predict behavior.

• structure() As an alternative, Use class<-, names<-, and attr<- to set attributes.

• Sys.setenv() As an alternative, use withr::with_envvar() for a temporary change instead of permanently modifying global environment variables.

• Sys.setlocale() As an alternative, use withr::with_locale() for a temporary change instead of permanently modifying the session locale.

• trace() As an alternative, remove this likely leftover from debugging. It traps a function and causes execution of arbitrary code when that function is run.

• undebug() As an alternative, remove this likely leftover from debugging. It is only useful for interactive debugging with debug().

• untrace() As an alternative, remove this likely leftover from debugging. It is only useful for interactive debugging with trace().

The following operators are sometimes regarded as undesirable:

• <<-. It assigns outside the current environment in a way that can be hard to reason about. Prefer fully-encapsulated functions wherever possible, or, if necessary, assign to a specific environment with assign(). Recall that you can create an environment at the desired scope with new.env().

• :::. It accesses non-exported functions inside packages. Code relying on these is likely to break in future versions of the package because the functions are not part of the public interface and may be changed or removed by the maintainers without notice. Use public functions via :: instead.

• <<-. It assigns outside the current environment in a way that can be hard to reason about. Prefer fully-encapsulated functions wherever possible, or, if necessary, assign to a specific environment with assign(). Recall that you can create an environment at the desired scope with new.env().

Description

anyDuplicated() exists as a replacement for any(duplicated(.)), which is more efficient for simple objects, and is at worst equally efficient. Therefore, it should be used in all situations instead of the latter.

Usage

any_duplicated_linter()

Details

Also match usage like length(unique(x$col)) == nrow(x), which can be replaced by anyDuplicated(x$col) == 0L.

Tags

best_practices, efficiency

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "any(duplicated(x), na.rm = TRUE)",
  linters = any_duplicated_linter()
)

lint(
  text = "length(unique(x)) == length(x)",
  linters = any_duplicated_linter()
)

# okay
lint(
  text = "anyDuplicated(x)",
  linters = any_duplicated_linter()
)

lint(
  text = "anyDuplicated(x) == 0L",
  linters = any_duplicated_linter()
)

Description

anyNA() exists as a replacement for any(is.na(x)) which is more efficient for simple objects, and is at worst equally efficient. Therefore, it should be used in all situations instead of the latter.

Usage

any_is_na_linter()

Tags

best_practices, efficiency

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "any(is.na(x), na.rm = TRUE)",
  linters = any_is_na_linter()
)

lint(
  text = "any(is.na(foo(x)))",
  linters = any_is_na_linter()
)

# okay
lint(
  text = "anyNA(x)",
  linters = any_is_na_linter()
)

lint(
  text = "anyNA(foo(x))",
  linters = any_is_na_linter()
)

lint(
  text = "any(!is.na(x), na.rm = TRUE)",
  linters = any_is_na_linter()
)

Description

Check that ⁠<-⁠ is always used for assignment.

Usage

assignment_linter(
  allow_cascading_assign = TRUE,
  allow_right_assign = FALSE,
  allow_trailing = TRUE,
  allow_pipe_assign = FALSE
)

Arguments

Tags

configurable, consistency, default, style

See Also

• linters for a complete list of linters available in lintr.

• https://style.tidyverse.org/syntax.html#assignment-1

• https://style.tidyverse.org/pipes.html#assignment-2

Examples

# will produce lints
lint(
  text = "x = mean(x)",
  linters = assignment_linter()
)

code_lines <- "1 -> x\n2 ->> y"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = assignment_linter()
)

lint(
  text = "x %<>% as.character()",
  linters = assignment_linter()
)

# okay
lint(
  text = "x <- mean(x)",
  linters = assignment_linter()
)

code_lines <- "x <- 1\ny <<- 2"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = assignment_linter()
)

# customizing using arguments
code_lines <- "1 -> x\n2 ->> y"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = assignment_linter(allow_right_assign = TRUE)
)

lint(
  text = "x <<- 1",
  linters = assignment_linter(allow_cascading_assign = FALSE)
)

writeLines("foo(bar = \n 1)")
lint(
  text = "foo(bar = \n 1)",
  linters = assignment_linter(allow_trailing = FALSE)
)

lint(
  text = "x %<>% as.character()",
  linters = assignment_linter(allow_pipe_assign = TRUE)
)

Description

available_linters() obtains a tagged list of all Linters available in a package.

available_tags() searches for available tags.

Usage

available_linters(packages = "lintr", tags = NULL, exclude_tags = "deprecated")

available_tags(packages = "lintr")

Arguments

Value

available_linters returns a data frame with columns 'linter', 'package' and 'tags':

linter

A character column naming the function associated with the linter.

package

A character column containing the name of the package providing the linter.

tags

A list column containing tags associated with the linter.

available_tags returns a character vector of linter tags used by the packages.

Package Authors

To implement available_linters() for your package, include a file inst/lintr/linters.csv in your package. The CSV file must contain the columns 'linter' and 'tags', and be UTF-8 encoded. Additional columns will be silently ignored if present and the columns are identified by name. Each row describes a linter by

1. its function name (e.g. "assignment_linter") in the column 'linter'.

2. space-separated tags associated with the linter (e.g. "style consistency default") in the column 'tags'.

Tags should be snake_case.

See available_tags("lintr") to find out what tags are already used by lintr.

See Also

• linters for a complete list of linters available in lintr.

• available_tags() to retrieve the set of valid tags.

Examples

lintr_linters <- available_linters()

# If the package doesn't exist or isn't installed, an empty data frame will be returned
available_linters("does-not-exist")

lintr_linters2 <- available_linters(c("lintr", "does-not-exist"))
identical(lintr_linters, lintr_linters2)
available_tags()

Description

Check for usage of unavailable functions. Not reliable for testing r-devel dependencies.

Usage

backport_linter(r_version = getRversion(), except = character())

Arguments

Tags

configurable, package_development, robustness

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "trimws(x)",
  linters = backport_linter("3.0.0")
)

lint(
  text = "str2lang(x)",
  linters = backport_linter("3.2.0")
)

# okay
lint(
  text = "trimws(x)",
  linters = backport_linter("3.6.0")
)

lint(
  text = "str2lang(x)",
  linters = backport_linter("4.0.0")
)

lint(
  text = "str2lang(x)",
  linters = backport_linter("3.2.0", except = "str2lang")
)

Description

Linters checking the use of coding best practices, such as explicit typing of numeric constants.

Linters

The following linters are tagged with 'best_practices':

• absolute_path_linter

• any_duplicated_linter

• any_is_na_linter

• boolean_arithmetic_linter

• class_equals_linter

• commented_code_linter

• condition_call_linter

• condition_message_linter

• conjunct_test_linter

• cyclocomp_linter

• empty_assignment_linter

• expect_comparison_linter

• expect_length_linter

• expect_named_linter

• expect_not_linter

• expect_null_linter

• expect_s3_class_linter

• expect_s4_class_linter

• expect_true_false_linter

• expect_type_linter

• fixed_regex_linter

• for_loop_index_linter

• function_argument_linter

• function_return_linter

• if_switch_linter

• ifelse_censor_linter

• implicit_assignment_linter

• implicit_integer_linter

• is_numeric_linter

• length_levels_linter

• lengths_linter

• library_call_linter

• list_comparison_linter

• literal_coercion_linter

• nonportable_path_linter

• nrow_subset_linter

• nzchar_linter

• object_overwrite_linter

• outer_negation_linter

• paste_linter

• pipe_return_linter

• print_linter

• redundant_equals_linter

• redundant_ifelse_linter

• regex_subset_linter

• rep_len_linter

• routine_registration_linter

• scalar_in_linter

• seq_linter

• sort_linter

• stopifnot_all_linter

• system_file_linter

• T_and_F_symbol_linter

• terminal_close_linter

• undesirable_function_linter

• undesirable_operator_linter

• unnecessary_lambda_linter

• unnecessary_nesting_linter

• unnecessary_placeholder_linter

• unreachable_code_linter

• unused_import_linter

• vector_logic_linter

• yoda_test_linter

See Also

linters for a complete list of linters available in lintr.

Description

length(which(x == y)) == 0 is the same as !any(x == y), but the latter is more readable and more efficient.

Usage

boolean_arithmetic_linter()

Tags

best_practices, efficiency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "length(which(x == y)) == 0L",
  linters = boolean_arithmetic_linter()
)

lint(
  text = "sum(grepl(pattern, x)) == 0",
  linters = boolean_arithmetic_linter()
)

# okay
lint(
  text = "!any(x == y)",
  linters = boolean_arithmetic_linter()
)

lint(
  text = "!any(grepl(pattern, x))",
  linters = boolean_arithmetic_linter()
)

Description

Perform various style checks related to placement and spacing of curly braces:

Usage

brace_linter(allow_single_line = FALSE)

Arguments

Details

• Opening curly braces are never on their own line and are always followed by a newline.

• Opening curly braces have a space before them.

• Closing curly braces are on their own line unless they are followed by an ⁠else⁠.

• Closing curly braces in if conditions are on the same line as the corresponding ⁠else⁠.

• Either both or neither branch in if/⁠else⁠ use curly braces, i.e., either both branches use {...} or neither does.

• Functions spanning multiple lines use curly braces.

Tags

configurable, default, readability, style

See Also

• linters for a complete list of linters available in lintr.

• https://style.tidyverse.org/syntax.html#indenting

• https://style.tidyverse.org/syntax.html#if-statements

Examples

# will produce lints
lint(
  text = "f <- function() { 1 }",
  linters = brace_linter()
)

writeLines("if (TRUE) {\n return(1) }")
lint(
  text = "if (TRUE) {\n return(1) }",
  linters = brace_linter()
)

# okay
writeLines("f <- function() {\n  1\n}")
lint(
  text = "f <- function() {\n  1\n}",
  linters = brace_linter()
)

writeLines("if (TRUE) { \n return(1) \n}")
lint(
  text = "if (TRUE) { \n return(1) \n}",
  linters = brace_linter()
)

# customizing using arguments
writeLines("if (TRUE) { return(1) }")
lint(
  text = "if (TRUE) { return(1) }",
  linters = brace_linter(allow_single_line = TRUE)
)

Description

Generate a report of the linting results using the Checkstyle XML format.

Usage

checkstyle_output(lints, filename = "lintr_results.xml")

Arguments

Description

Usage like class(x) == "character" is prone to error since class in R is in general a vector. The correct version for S3 classes is inherits(): inherits(x, "character"). Often, class k will have an is. equivalent, for example is.character() or is.data.frame().

Usage

class_equals_linter()

Details

Similar reasoning applies for class(x) %in% "character".

Tags

best_practices, consistency, robustness

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = 'is_lm <- class(x) == "lm"',
  linters = class_equals_linter()
)

lint(
  text = 'if ("lm" %in% class(x)) is_lm <- TRUE',
  linters = class_equals_linter()
)

# okay
lint(
  text = 'is_lm <- inherits(x, "lm")',
  linters = class_equals_linter()
)

lint(
  text = 'if (inherits(x, "lm")) is_lm <- TRUE',
  linters = class_equals_linter()
)

Description

Clear the lintr cache

Usage

clear_cache(file = NULL, path = NULL)

Arguments

Value

0 for success, 1 for failure, invisibly.

Description

Check that all commas are followed by spaces, but do not have spaces before them.

Usage

commas_linter(allow_trailing = FALSE)

Arguments

Tags

configurable, default, readability, style

See Also

• linters for a complete list of linters available in lintr.

• https://style.tidyverse.org/syntax.html#commas

Examples

# will produce lints
lint(
  text = "switch(op , x = foo, y = bar)",
  linters = commas_linter()
)

lint(
  text = "mean(x,trim = 0.2,na.rm = TRUE)",
  linters = commas_linter()
)

lint(
  text = "x[ ,, drop=TRUE]",
  linters = commas_linter()
)

lint(
  text = "x[1,]",
  linters = commas_linter()
)

# okay
lint(
  text = "switch(op, x = foo, y = bar)",
  linters = commas_linter()
)

lint(
  text = "switch(op, x = , y = bar)",
  linters = commas_linter()
)

lint(
  text = "mean(x, trim = 0.2, na.rm = TRUE)",
  linters = commas_linter()
)

lint(
  text = "a[1, , 2, , 3]",
  linters = commas_linter()
)

lint(
  text = "x[1,]",
  linters = commas_linter(allow_trailing = TRUE)
)

Description

Check that there is no commented code outside roxygen blocks.

Usage

commented_code_linter()

Tags

best_practices, default, readability, style

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "# x <- 1",
  linters = commented_code_linter()
)

lint(
  text = "x <- f() # g()",
  linters = commented_code_linter()
)

lint(
  text = "x + y # + z[1, 2]",
  linters = commented_code_linter()
)

# okay
lint(
  text = "x <- 1; x <- f(); x + y",
  linters = commented_code_linter()
)

lint(
  text = "#' x <- 1",
  linters = commented_code_linter()
)

Description

Linters highlighting common mistakes, such as duplicate arguments.

Linters

The following linters are tagged with 'common_mistakes':

• duplicate_argument_linter

• equals_na_linter

• length_test_linter

• list_comparison_linter

• missing_argument_linter

• missing_package_linter

• pipe_return_linter

• redundant_equals_linter

• sprintf_linter

• unused_import_linter

• vector_logic_linter

See Also

linters for a complete list of linters available in lintr.

Description

!(x == y) is more readably expressed as x != y. The same is true of other negations of simple comparisons like !(x > y) and !(x <= y).

Usage

comparison_negation_linter()

Tags

consistency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "!x == 2",
  linters = comparison_negation_linter()
)

lint(
  text = "!(x > 2)",
  linters = comparison_negation_linter()
)

# okay
lint(
  text = "!(x == 2 & y > 2)",
  linters = comparison_negation_linter()
)

lint(
  text = "!(x & y)",
  linters = comparison_negation_linter()
)

lint(
  text = "x != 2",
  linters = comparison_negation_linter()
)

Description

This linter, with the default display_call = FALSE, enforces the recommendation of the tidyverse design guide regarding displaying error calls.

Usage

condition_call_linter(display_call = FALSE)

Arguments

Tags

best_practices, configurable, style, tidy_design

See Also

• linters for a complete list of linters available in lintr.

• https://design.tidyverse.org/err-call.html>

Examples

# will produce lints
lint(
  text = "stop('test')",
  linters = condition_call_linter()
)

lint(
  text = "stop('test', call. = TRUE)",
  linters = condition_call_linter()
)

lint(
  text = "stop('test', call. = FALSE)",
  linters = condition_call_linter(display_call = TRUE)
)

lint(
  text = "stop('this is a', 'test', call. = FALSE)",
  linters = condition_call_linter(display_call = TRUE)
)

# okay
lint(
  text = "stop('test', call. = FALSE)",
  linters = condition_call_linter()
)

lint(
  text = "stop('this is a', 'test', call. = FALSE)",
  linters = condition_call_linter()
)

lint(
  text = "stop('test', call. = TRUE)",
  linters = condition_call_linter(display_call = TRUE)
)

Description

This linter discourages combining condition functions like stop() with string concatenation functions paste() and paste0(). This is because

• stop(paste0(...)) is redundant as it is exactly equivalent to stop(...)

• stop(paste(...)) is similarly equivalent to stop(...) with separators (see examples)

The same applies to the other default condition functions as well, i.e., warning(), message(), and packageStartupMessage().

Usage

condition_message_linter()

Tags

best_practices, consistency

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = 'stop(paste("a string", "another"))',
  linters = condition_message_linter()
)

lint(
  text = 'warning(paste0("a string", " another"))',
  linters = condition_message_linter()
)

# okay
lint(
  text = 'stop("a string", " another")',
  linters = condition_message_linter()
)

lint(
  text = 'warning("a string", " another")',
  linters = condition_message_linter()
)

lint(
  text = 'warning(paste("a string", "another", sep = "-"))',
  linters = condition_message_linter()
)

Description

Generic linters which support custom configuration to your needs.

Linters

The following linters are tagged with 'configurable':

• absolute_path_linter

• assignment_linter

• backport_linter

• brace_linter

• commas_linter

• condition_call_linter

• conjunct_test_linter

• consecutive_mutate_linter

• cyclocomp_linter

• duplicate_argument_linter

• fixed_regex_linter

• if_not_else_linter

• if_switch_linter

• implicit_assignment_linter

• implicit_integer_linter

• indentation_linter

• infix_spaces_linter

• library_call_linter

• line_length_linter

• missing_argument_linter

• namespace_linter

• nested_pipe_linter

• nonportable_path_linter

• object_length_linter

• object_name_linter

• object_overwrite_linter

• object_usage_linter

• paste_linter

• pipe_consistency_linter

• quotes_linter

• redundant_ifelse_linter

• return_linter

• scalar_in_linter

• semicolon_linter

• string_boundary_linter

• todo_comment_linter

• trailing_whitespace_linter

• undesirable_function_linter

• undesirable_operator_linter

• unnecessary_concatenation_linter

• unnecessary_lambda_linter

• unnecessary_nesting_linter

• unreachable_code_linter

• unused_import_linter

See Also

linters for a complete list of linters available in lintr.

Description

For readability of test outputs, testing only one thing per call to testthat::expect_true() is preferable, i.e., ⁠expect_true(A); expect_true(B)⁠ is better than expect_true(A && B), and ⁠expect_false(A); expect_false(B)⁠ is better than expect_false(A || B).

Usage

conjunct_test_linter(
  allow_named_stopifnot = TRUE,
  allow_filter = c("never", "not_dplyr", "always")
)

Arguments

Details

Similar reasoning applies to && usage inside stopifnot() and assertthat::assert_that() calls.

Relatedly, dplyr::filter(DF, A & B) is the same as dplyr::filter(DF, A, B), but the latter will be more readable / easier to format for long conditions. Note that this linter assumes usages of filter() are dplyr::filter(); if you're using another function named filter(), e.g. stats::filter(), please namespace-qualify it to avoid false positives. You can omit linting filter() expressions altogether via allow_filter = TRUE.

Tags

best_practices, configurable, package_development, pkg_testthat, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "expect_true(x && y)",
  linters = conjunct_test_linter()
)

lint(
  text = "expect_false(x || (y && z))",
  linters = conjunct_test_linter()
)

lint(
  text = "stopifnot('x must be a logical scalar' = length(x) == 1 && is.logical(x) && !is.na(x))",
  linters = conjunct_test_linter(allow_named_stopifnot = FALSE)
)

lint(
  text = "dplyr::filter(mtcars, mpg > 20 & vs == 0)",
  linters = conjunct_test_linter()
)

lint(
  text = "filter(mtcars, mpg > 20 & vs == 0)",
  linters = conjunct_test_linter()
)

# okay
lint(
  text = "expect_true(x || (y && z))",
  linters = conjunct_test_linter()
)

lint(
  text = 'stopifnot("x must be a logical scalar" = length(x) == 1 && is.logical(x) && !is.na(x))',
  linters = conjunct_test_linter(allow_named_stopifnot = TRUE)
)

lint(
  text = "dplyr::filter(mtcars, mpg > 20 & vs == 0)",
  linters = conjunct_test_linter(allow_filter = "always")
)

lint(
  text = "filter(mtcars, mpg > 20 & vs == 0)",
  linters = conjunct_test_linter(allow_filter = "not_dplyr")
)

lint(
  text = "stats::filter(mtcars$cyl, mtcars$mpg > 20 & mtcars$vs == 0)",
  linters = conjunct_test_linter()
)

Description

stopifnot() accepts any number of tests, so sequences like ⁠stopifnot(x); stopifnot(y)⁠ are redundant. Ditto for tests using assertthat::assert_that() without specifying ⁠msg=⁠.

Usage

consecutive_assertion_linter()

Tags

consistency, readability, style

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "stopifnot(x); stopifnot(y)",
  linters = consecutive_assertion_linter()
)

lint(
  text = "assert_that(x); assert_that(y)",
  linters = consecutive_assertion_linter()
)

# okay
lint(
  text = "stopifnot(x, y)",
  linters = consecutive_assertion_linter()
)

lint(
  text = 'assert_that(x, msg = "Bad x!"); assert_that(y)',
  linters = consecutive_assertion_linter()
)

Description

dplyr::mutate() accepts any number of columns, so sequences like DF %>% dplyr::mutate(..1) %>% dplyr::mutate(..2) are redundant – they can always be expressed with a single call to dplyr::mutate().

Usage

consecutive_mutate_linter(invalid_backends = "dbplyr")

Arguments

Details

An exception is for some SQL back-ends, where the translation logic may not be as sophisticated as that in the default dplyr, for example in DF %>% mutate(a = a + 1) %>% mutate(b = a - 2).

Tags

configurable, consistency, efficiency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "x %>% mutate(a = 1) %>% mutate(b = 2)",
  linters = consecutive_mutate_linter()
)

# okay
lint(
  text = "x %>% mutate(a = 1, b = 2)",
  linters = consecutive_mutate_linter()
)

code <- "library(dbplyr)\nx %>% mutate(a = 1) %>% mutate(a = a + 1)"
writeLines(code)
lint(
  text = code,
  linters = consecutive_mutate_linter()
)

Description

Linters checking enforcing a consistent alternative if there are multiple syntactically valid ways to write something.

Linters

The following linters are tagged with 'consistency':

• assignment_linter

• class_equals_linter

• comparison_negation_linter

• condition_message_linter

• consecutive_assertion_linter

• consecutive_mutate_linter

• function_argument_linter

• if_not_else_linter

• if_switch_linter

• implicit_integer_linter

• inner_combine_linter

• is_numeric_linter

• keyword_quote_linter

• length_levels_linter

• literal_coercion_linter

• nested_pipe_linter

• nrow_subset_linter

• numeric_leading_zero_linter

• nzchar_linter

• object_name_linter

• paste_linter

• print_linter

• quotes_linter

• redundant_ifelse_linter

• rep_len_linter

• scalar_in_linter

• seq_linter

• system_file_linter

• T_and_F_symbol_linter

• unnecessary_nesting_linter

• which_grepl_linter

• whitespace_linter

See Also

linters for a complete list of linters available in lintr.

Description

Linters highlighting possible programming mistakes, such as unused variables.

Linters

The following linters are tagged with 'correctness':

• duplicate_argument_linter

• equals_na_linter

• missing_argument_linter

• namespace_linter

• object_usage_linter

• package_hooks_linter

• sprintf_linter

See Also

linters for a complete list of linters available in lintr.

Description

Check for overly complicated expressions. See cyclocomp() function from {cyclocomp}.

Usage

cyclocomp_linter(complexity_limit = 15L)

Arguments

Tags

best_practices, configurable, readability, style

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "if (TRUE) 1 else 2",
  linters = cyclocomp_linter(complexity_limit = 1L)
)

# okay
lint(
  text = "if (TRUE) 1 else 2",
  linters = cyclocomp_linter(complexity_limit = 2L)
)

Description

List of default linters for lint(). Use linters_with_defaults() to customize it. Most of the default linters are based on the tidyverse style guide.

The set of default linters is as follows (any parameterized linters, e.g., line_length_linter use their default argument(s), see ⁠?<linter_name>⁠ for details):

Usage

default_linters

Format

An object of class list of length 25.

Linters

The following linters are tagged with 'default':

• assignment_linter

• brace_linter

• commas_linter

• commented_code_linter

• equals_na_linter

• function_left_parentheses_linter

• indentation_linter

• infix_spaces_linter

• line_length_linter

• object_length_linter

• object_name_linter

• object_usage_linter

• paren_body_linter

• pipe_continuation_linter

• quotes_linter

• return_linter

• semicolon_linter

• seq_linter

• spaces_inside_linter

• spaces_left_parentheses_linter

• T_and_F_symbol_linter

• trailing_blank_lines_linter

• trailing_whitespace_linter

• vector_logic_linter

• whitespace_linter

See Also

linters for a complete list of linters available in lintr.

Description

The default settings consist of

• linters: a list of default linters (see default_linters())

• encoding: the character encoding assumed for the file

• exclude: pattern used to exclude a line of code

• exclude_start, exclude_end: patterns used to mark start and end of the code block to exclude

• exclude_linter, exclude_linter_sep: patterns used to exclude linters

• exclusions: a list of exclusions, see exclude() for a complete description of valid values.

• cache_directory: location of cache directory

• comment_token: a GitHub token character

• error_on_lint: decides if error should be produced when any lints are found

There are no settings without defaults, i.e., this list describes every valid setting.

Usage

default_settings

Format

An object of class list of length 12.

See Also

read_settings(), default_linters

Examples

# available settings
names(default_settings)

# linters included by default
names(default_settings$linters)

# default values for a few of the other settings
default_settings[c(
  "encoding",
  "exclude",
  "exclude_start",
  "exclude_end",
  "exclude_linter",
  "exclude_linter_sep",
  "exclusions",
  "error_on_lint"
)]

Description

Linters that are deprecated and provided for backwards compatibility only. These linters will be excluded from linters_with_tags() by default.

Linters

The following linters are tagged with 'deprecated':

• consecutive_stopifnot_linter

• extraction_operator_linter

• no_tab_linter

• single_quotes_linter

• unnecessary_nested_if_linter

• unneeded_concatenation_linter

See Also

linters for a complete list of linters available in lintr.

Description

Check for duplicate arguments in function calls. Some cases are run-time errors (e.g. mean(x = 1:5, x = 2:3)), otherwise this linter is used to discourage explicitly providing duplicate names to objects (e.g. c(a = 1, a = 2)). Duplicate-named objects are hard to work with programmatically and should typically be avoided.

Usage

duplicate_argument_linter(except = c("mutate", "transmute"))

Arguments

Tags

common_mistakes, configurable, correctness

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "list(x = 1, x = 2)",
  linters = duplicate_argument_linter()
)

lint(
  text = "fun(arg = 1, arg = 2)",
  linters = duplicate_argument_linter()
)

# okay
lint(
  text = "list(x = 1, x = 2)",
  linters = duplicate_argument_linter(except = "list")
)

lint(
  text = "df %>% dplyr::mutate(x = a + b, x = x + d)",
  linters = duplicate_argument_linter()
)

Description

Linters highlighting code efficiency problems, such as unnecessary function calls.

Linters

The following linters are tagged with 'efficiency':

• any_duplicated_linter

• any_is_na_linter

• boolean_arithmetic_linter

• consecutive_mutate_linter

• fixed_regex_linter

• if_switch_linter

• ifelse_censor_linter

• inner_combine_linter

• length_test_linter

• lengths_linter

• literal_coercion_linter

• matrix_apply_linter

• nested_ifelse_linter

• nrow_subset_linter

• nzchar_linter

• outer_negation_linter

• redundant_equals_linter

• redundant_ifelse_linter

• regex_subset_linter

• routine_registration_linter

• sample_int_linter

• scalar_in_linter

• seq_linter

• sort_linter

• string_boundary_linter

• unnecessary_concatenation_linter

• unnecessary_lambda_linter

• vector_logic_linter

• which_grepl_linter

See Also

linters for a complete list of linters available in lintr.

Description

Assignment of {} is the same as assignment of NULL; use the latter for clarity. Closely related: unnecessary_concatenation_linter().

Usage

empty_assignment_linter()

Tags

best_practices, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "x <- {}",
  linters = empty_assignment_linter()
)

writeLines("x = {\n}")
lint(
  text = "x = {\n}",
  linters = empty_assignment_linter()
)

# okay
lint(
  text = "x <- { 3 + 4 }",
  linters = empty_assignment_linter()
)

lint(
  text = "x <- NULL",
  linters = empty_assignment_linter()
)

Description

Check for x == NA, x != NA and x %in% NA. Such usage is almost surely incorrect – checks for missing values should be done with is.na().

Usage

equals_na_linter()

Tags

common_mistakes, correctness, default, robustness

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "x == NA",
  linters = equals_na_linter()
)

lint(
  text = "x != NA",
  linters = equals_na_linter()
)

lint(
  text = "x %in% NA",
  linters = equals_na_linter()
)

# okay
lint(
  text = "is.na(x)",
  linters = equals_na_linter()
)

lint(
  text = "!is.na(x)",
  linters = equals_na_linter()
)

Description

Linters that evaluate parts of the linted code, such as loading referenced packages. These linters should not be used with untrusted code, and may need dependencies of the linted package or project to be available in order to function correctly. For package authors, note that this includes loading the package itself, e.g. with pkgload::load_all() or installing and attaching the package.

Linters

The following linters are tagged with 'executing':

• namespace_linter

• object_length_linter

• object_name_linter

• object_overwrite_linter

• object_usage_linter

• unused_import_linter

See Also

linters for a complete list of linters available in lintr.

Description

testthat::expect_gt(), testthat::expect_gte(), testthat::expect_lt(), testthat::expect_lte(), and testthat::expect_equal() exist specifically for testing comparisons between two objects. testthat::expect_true() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_comparison_linter()

Tags

best_practices, package_development, pkg_testthat

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "expect_true(x > y)",
  linters = expect_comparison_linter()
)

lint(
  text = "expect_true(x <= y)",
  linters = expect_comparison_linter()
)

lint(
  text = "expect_true(x == (y == 2))",
  linters = expect_comparison_linter()
)

# okay
lint(
  text = "expect_gt(x, y)",
  linters = expect_comparison_linter()
)

lint(
  text = "expect_lte(x, y)",
  linters = expect_comparison_linter()
)

lint(
  text = "expect_identical(x, y == 2)",
  linters = expect_comparison_linter()
)

lint(
  text = "expect_true(x < y | x > y^2)",
  linters = expect_comparison_linter()
)

Description

This linter enforces the usage of testthat::expect_identical() as the default expectation for comparisons in a testthat suite. expect_true(identical(x, y)) is an equivalent but unadvised method of the same test. Further, testthat::expect_equal() should only be used when expect_identical() is inappropriate, i.e., when x and y need only be numerically equivalent instead of fully identical (in which case, provide the ⁠tolerance=⁠ argument to expect_equal() explicitly). This also applies when it's inconvenient to check full equality (e.g., names can be ignored, in which case ignore_attr = "names" should be supplied to expect_equal() (or, for 2nd edition, check.attributes = FALSE).

Usage

expect_identical_linter()

Exceptions

The linter allows expect_equal() in three circumstances:

1. A named argument is set (e.g. ignore_attr or tolerance)

2. Comparison is made to an explicit decimal, e.g. expect_equal(x, 1.0) (implicitly setting tolerance)

3. ... is passed (wrapper functions which might set arguments such as ignore_attr or tolerance)

Tags

package_development, pkg_testthat

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "expect_equal(x, y)",
  linters = expect_identical_linter()
)

lint(
  text = "expect_true(identical(x, y))",
  linters = expect_identical_linter()
)

# okay
lint(
  text = "expect_identical(x, y)",
  linters = expect_identical_linter()
)

lint(
  text = "expect_equal(x, y, check.attributes = FALSE)",
  linters = expect_identical_linter()
)

lint(
  text = "expect_equal(x, y, tolerance = 1e-6)",
  linters = expect_identical_linter()
)

Description

testthat::expect_length() exists specifically for testing the length() of an object. testthat::expect_equal() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_length_linter()

Tags

best_practices, package_development, pkg_testthat, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "expect_equal(length(x), 2L)",
  linters = expect_length_linter()
)

# okay
lint(
  text = "expect_length(x, 2L)",
  linters = expect_length_linter()
)

Description

These are expectation functions to test specified linters on sample code in the testthat testing framework.

• expect_lint asserts that specified lints are generated.

• expect_no_lint asserts that no lints are generated.

Usage

expect_lint(content, checks, ..., file = NULL, language = "en")

expect_no_lint(content, ..., file = NULL, language = "en")

Arguments

Value

NULL, invisibly.

Examples

# no expected lint
expect_no_lint("a", trailing_blank_lines_linter())

# one expected lint
expect_lint("a\n", "trailing blank", trailing_blank_lines_linter())
expect_lint("a\n", list(message = "trailing blank", line_number = 2), trailing_blank_lines_linter())

# several expected lints
expect_lint("a\n\n", list("trailing blank", "trailing blank"), trailing_blank_lines_linter())
expect_lint(
  "a\n\n",
  list(
    list(message = "trailing blank", line_number = 2),
    list(message = "trailing blank", line_number = 3)
  ),
  trailing_blank_lines_linter()
)

Description

This function is a thin wrapper around lint_package that simply tests there are no lints in the package. It can be used to ensure that your tests fail if the package contains lints.

Usage

expect_lint_free(...)

Arguments

Description

testthat::expect_named() exists specifically for testing the names() of an object. testthat::expect_equal() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_named_linter()

Tags

best_practices, package_development, pkg_testthat, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = 'expect_equal(names(x), "a")',
  linters = expect_named_linter()
)

# okay
lint(
  text = 'expect_named(x, "a")',
  linters = expect_named_linter()
)

lint(
  text = 'expect_equal(colnames(x), "a")',
  linters = expect_named_linter()
)

lint(
  text = 'expect_equal(dimnames(x), "a")',
  linters = expect_named_linter()
)

Description

testthat::expect_false() exists specifically for testing that an output is FALSE. testthat::expect_true() can also be used for such tests by negating the output, but it is better to use the tailored function instead. The reverse is also true – use expect_false(A) instead of expect_true(!A).

Usage

expect_not_linter()

Tags

best_practices, package_development, pkg_testthat, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "expect_true(!x)",
  linters = expect_not_linter()
)

# okay
lint(
  text = "expect_false(x)",
  linters = expect_not_linter()
)

Description

Require usage of expect_null(x) over expect_equal(x, NULL) and similar usages.

Usage

expect_null_linter()

Details

testthat::expect_null() exists specifically for testing for NULL objects. testthat::expect_equal(), testthat::expect_identical(), and testthat::expect_true() can also be used for such tests, but it is better to use the tailored function instead.

Tags

best_practices, package_development, pkg_testthat

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "expect_equal(x, NULL)",
  linters = expect_null_linter()
)

lint(
  text = "expect_identical(x, NULL)",
  linters = expect_null_linter()
)

lint(
  text = "expect_true(is.null(x))",
  linters = expect_null_linter()
)


# okay
lint(
  text = "expect_null(x)",
  linters = expect_null_linter()
)

Description

testthat::expect_s3_class() exists specifically for testing the class of S3 objects. testthat::expect_equal(), testthat::expect_identical(), and testthat::expect_true() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_s3_class_linter()

Tags

best_practices, package_development, pkg_testthat

See Also

• linters for a complete list of linters available in lintr.

• expect_s4_class_linter()

Examples

# will produce lints
lint(
  text = 'expect_equal(class(x), "data.frame")',
  linters = expect_s3_class_linter()
)

lint(
  text = 'expect_equal(class(x), "numeric")',
  linters = expect_s3_class_linter()
)

# okay
lint(
  text = 'expect_s3_class(x, "data.frame")',
  linters = expect_s3_class_linter()
)

lint(
  text = 'expect_type(x, "double")',
  linters = expect_s3_class_linter()
)

Description

testthat::expect_s4_class() exists specifically for testing the class of S4 objects. testthat::expect_true() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_s4_class_linter()

Tags

best_practices, package_development, pkg_testthat

See Also

• linters for a complete list of linters available in lintr.

• expect_s3_class_linter()

Examples

# will produce lints
lint(
  text = 'expect_true(is(x, "Matrix"))',
  linters = expect_s4_class_linter()
)

# okay
lint(
  text = 'expect_s4_class(x, "Matrix")',
  linters = expect_s4_class_linter()
)

Description

testthat::expect_true() and testthat::expect_false() exist specifically for testing the TRUE/FALSE value of an object. testthat::expect_equal() and testthat::expect_identical() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_true_false_linter()

Tags

best_practices, package_development, pkg_testthat, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "expect_equal(x, TRUE)",
  linters = expect_true_false_linter()
)

lint(
  text = "expect_equal(x, FALSE)",
  linters = expect_true_false_linter()
)

# okay
lint(
  text = "expect_true(x)",
  linters = expect_true_false_linter()
)

lint(
  text = "expect_false(x)",
  linters = expect_true_false_linter()
)

Description

testthat::expect_type() exists specifically for testing the storage type of objects. testthat::expect_equal(), testthat::expect_identical(), and testthat::expect_true() can also be used for such tests, but it is better to use the tailored function instead.

Usage

expect_type_linter()

Tags

best_practices, package_development, pkg_testthat

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = 'expect_equal(typeof(x), "double")',
  linters = expect_type_linter()
)

lint(
  text = 'expect_identical(typeof(x), "double")',
  linters = expect_type_linter()
)

# okay
lint(
  text = 'expect_type(x, "double")',
  linters = expect_type_linter()
)

Description

Invoking a regular expression engine is overkill for cases when the search pattern only involves static patterns.

Usage

fixed_regex_linter(allow_unescaped = FALSE)

Arguments

Details

NB: for stringr functions, that means wrapping the pattern in stringr::fixed().

NB: this linter is likely not able to distinguish every possible case when a fixed regular expression is preferable, rather it seeks to identify likely cases. It should never report false positives, however; please report false positives as an error.

Tags

best_practices, configurable, efficiency, readability, regex

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
code_lines <- 'gsub("\\\\.", "", x)'
writeLines(code_lines)
lint(
  text = code_lines,
  linters = fixed_regex_linter()
)

lint(
  text = 'grepl("a[*]b", x)',
  linters = fixed_regex_linter()
)

lint(
  text = 'grepl("a[*]b", x)',
  linters = fixed_regex_linter(allow_unescaped = TRUE)
)

code_lines <- 'stringr::str_subset(x, "\\\\$")'
writeLines(code_lines)
lint(
  text = code_lines,
  linters = fixed_regex_linter()
)

lint(
  text = 'grepl("Munich", address)',
  linters = fixed_regex_linter()
)

# okay
code_lines <- 'gsub("\\\\.", "", x, fixed = TRUE)'
writeLines(code_lines)
lint(
  text = code_lines,
  linters = fixed_regex_linter()
)

lint(
  text = 'grepl("a*b", x, fixed = TRUE)',
  linters = fixed_regex_linter()
)

lint(
  text = 'stringr::str_subset(x, stringr::fixed("$"))',
  linters = fixed_regex_linter()
)

lint(
  text = 'grepl("Munich", address, fixed = TRUE)',
  linters = fixed_regex_linter()
)

lint(
  text = 'grepl("Munich", address)',
  linters = fixed_regex_linter(allow_unescaped = TRUE)
)

Description

⁠for (x in x)⁠ is a poor choice of indexing variable. This overwrites x in the calling scope and is confusing to read.

Usage

for_loop_index_linter()

Tags

best_practices, readability, robustness

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "for (x in x) { TRUE }",
  linters = for_loop_index_linter()
)

lint(
  text = "for (x in foo(x, y)) { TRUE }",
  linters = for_loop_index_linter()
)

# okay
lint(
  text = "for (xi in x) { TRUE }",
  linters = for_loop_index_linter()
)

lint(
  text = "for (col in DF$col) { TRUE }",
  linters = for_loop_index_linter()
)

Description

Check that arguments with defaults come last in all function declarations, as per the tidyverse design guide.

Changing the argument order can be a breaking change. An alternative to changing the argument order is to instead set the default for such arguments to NULL.

Usage

function_argument_linter()

Tags

best_practices, consistency, style

See Also

• linters for a complete list of linters available in lintr.

• https://design.tidyverse.org/required-no-defaults.html

Examples

# will produce lints
lint(
  text = "function(y = 1, z = 2, x) {}",
  linters = function_argument_linter()
)

lint(
  text = "function(x, y, z = 1, ..., w) {}",
  linters = function_argument_linter()
)

# okay
lint(
  text = "function(x, y = 1, z = 2) {}",
  linters = function_argument_linter()
)

lint(
  text = "function(x, y, w, z = 1, ...) {}",
  linters = function_argument_linter()
)

lint(
  text = "function(y = 1, z = 2, x = NULL) {}",
  linters = function_argument_linter()
)

lint(
  text = "function(x, y, z = 1, ..., w = NULL) {}",
  linters = function_argument_linter()
)

Description

Check that all left parentheses in a function call do not have spaces before them (e.g. mean (1:3)). Although this is syntactically valid, it makes the code difficult to read.

Usage

function_left_parentheses_linter()

Details

Exceptions are made for control flow functions (if, for, etc.).

Tags

default, readability, style

See Also

• linters for a complete list of linters available in lintr.

• https://style.tidyverse.org/syntax.html#parentheses

• spaces_left_parentheses_linter()

Examples

# will produce lints
lint(
  text = "mean (x)",
  linters = function_left_parentheses_linter()
)

lint(
  text = "stats::sd(c (x, y, z))",
  linters = function_left_parentheses_linter()
)

# okay
lint(
  text = "mean(x)",
  linters = function_left_parentheses_linter()
)

lint(
  text = "stats::sd(c(x, y, z))",
  linters = function_left_parentheses_linter()
)

lint(
  text = "foo <- function(x) (x + 1)",
  linters = function_left_parentheses_linter()
)

Description

return(x <- ...) is either distracting (because x is ignored), or confusing (because assigning to x has some side effect that is muddled by the dual-purpose expression).

Usage

function_return_linter()

Tags

best_practices, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "foo <- function(x) return(y <- x + 1)",
  linters = function_return_linter()
)

lint(
  text = "foo <- function(x) return(x <<- x + 1)",
  linters = function_return_linter()
)

writeLines("e <- new.env() \nfoo <- function(x) return(e$val <- x + 1)")
lint(
  text = "e <- new.env() \nfoo <- function(x) return(e$val <- x + 1)",
  linters = function_return_linter()
)

# okay
lint(
  text = "foo <- function(x) return(x + 1)",
  linters = function_return_linter()
)

code_lines <- "
foo <- function(x) {
  x <<- x + 1
  return(x)
}
"
lint(
  text = code_lines,
  linters = function_return_linter()
)

code_lines <- "
e <- new.env()
foo <- function(x) {
  e$val <- x + 1
  return(e$val)
}
"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = function_return_linter()
)

Description

Convert STR_CONST text() values into R strings. This is useful to account for arbitrary character literals, e.g. R"------[hello]------", which is parsed in R as "hello". It is quite cumbersome to write XPaths allowing for strings like this, so whenever your linter logic requires testing a STR_CONST node's value, use this function. NB: this is also properly vectorized on s, and accepts a variety of inputs. Empty inputs will become NA outputs, which helps ensure that length(get_r_string(s)) == length(s).

Usage

get_r_string(s, xpath = NULL)

Arguments

Examples

tmp <- tempfile()
writeLines("c('a', 'b')", tmp)
expr_as_xml <- get_source_expressions(tmp)$expressions[[1L]]$xml_parsed_content
writeLines(as.character(expr_as_xml))
get_r_string(expr_as_xml, "expr[2]")
get_r_string(expr_as_xml, "expr[3]")
unlink(tmp)

# more importantly, extract raw strings correctly
tmp_raw <- tempfile()
writeLines("c(R'(a\\b)', R'--[a\\\"\'\"\\b]--')", tmp_raw)
expr_as_xml_raw <- get_source_expressions(tmp_raw)$expressions[[1L]]$xml_parsed_content
writeLines(as.character(expr_as_xml_raw))
get_r_string(expr_as_xml_raw, "expr[2]")
get_r_string(expr_as_xml_raw, "expr[3]")
unlink(tmp_raw)

Description

This object is given as input to each linter.

Usage

get_source_expressions(filename, lines = NULL)

Arguments

Details

The file is read using the encoding setting. This setting is found by taking the first valid result from the following locations

1. The encoding key from the usual lintr configuration settings.

2. The Encoding field from a Package DESCRIPTION file in a parent directory.

3. The Encoding field from an R Project .Rproj file in a parent directory.

4. "UTF-8" as a fallback.

Value

A list with three components:

expressions

a list of n+1 objects. The first n elements correspond to each expression in filename, and consist of a list of 8 elements:

• filename (character) the name of the file.

• line (integer) the line in the file where this expression begins.

• column (integer) the column in the file where this expression begins.

• lines (named character) vector of all lines spanned by this expression, named with the corresponding line numbers.

• parsed_content (data.frame) as given by utils::getParseData() for this expression.

• xml_parsed_content (xml_document) the XML parse tree of this expression as given by xmlparsedata::xml_parse_data().

• content (character) the same as lines as a single string (not split across lines).

• xml_find_function_calls(function_names) (function) a function that returns all SYMBOL_FUNCTION_CALL XML nodes from xml_parsed_content with specified function names.

The final element of expressions is a list corresponding to the full file consisting of 7 elements:

• filename (character) the name of this file.

• file_lines (character) the readLines() output for this file.

• content (character) for .R files, the same as file_lines; for .Rmd or .qmd scripts, this is the extracted R source code (as text).

• full_parsed_content (data.frame) as given by utils::getParseData() for the full content.

• full_xml_parsed_content (xml_document) the XML parse tree of all expressions as given by xmlparsedata::xml_parse_data().

• terminal_newline (logical) records whether filename has a terminal newline (as determined by readLines() producing a corresponding warning).

• xml_find_function_calls(function_names) (function) a function that returns all SYMBOL_FUNCTION_CALL XML nodes from full_xml_parsed_content with specified function names.

error

A Lint object describing any parsing error.

lines

The readLines() output for this file.

Examples

tmp <- tempfile()
writeLines(c("x <- 1", "y <- x + 1"), tmp)
get_source_expressions(tmp)
unlink(tmp)

Description

Gets the source IDs (row indices) corresponding to given token.

Usage

ids_with_token(source_expression, value, fun = `==`, source_file = NULL)

with_id(source_expression, id, source_file)

Arguments

Value

ids_with_token: The indices of the parsed_content data frame entry of the list of source expressions. Indices correspond to the rows where fun evaluates to TRUE for the value in the token column.

with_id: A data frame corresponding to the row(s) specified in id.

Functions

• with_id(): Return the row of the parsed_content entry of the ⁠[get_source_expressions]()⁠ object. Typically used in conjunction with ids_with_token to iterate over rows containing desired tokens.

Examples

tmp <- tempfile()
writeLines(c("x <- 1", "y <- x + 1"), tmp)
source_exprs <- get_source_expressions(tmp)
ids_with_token(source_exprs$expressions[[1L]], value = "SYMBOL")
with_id(source_exprs$expressions[[1L]], 2L)
unlink(tmp)

Description

if (!A) x else y is the same as if (A) y else x, but the latter is easier to reason about in the ⁠else⁠ case. The former requires double negation that can be avoided by switching the statement order.

Usage

if_not_else_linter(exceptions = c("is.null", "is.na", "missing"))

Arguments

Details

This only applies in the simple ⁠if/else⁠ case. Statements like if (!A) x else if (B) y else z don't always have a simpler or more readable form.

It also applies to ifelse() and the package equivalents dplyr::if_else() and data.table::fifelse().

Tags

configurable, consistency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "if (!A) x else y",
  linters = if_not_else_linter()
)

lint(
  text = "if (!A) x else if (!B) y else z",
  linters = if_not_else_linter()
)

lint(
  text = "ifelse(!is_treatment, x, y)",
  linters = if_not_else_linter()
)

lint(
  text = "if (!is.null(x)) x else 2",
  linters = if_not_else_linter(exceptions = character())
)

# okay
lint(
  text = "if (A) x else y",
  linters = if_not_else_linter()
)

lint(
  text = "if (!A) x else if (B) z else y",
  linters = if_not_else_linter()
)

lint(
  text = "ifelse(is_treatment, y, x)",
  linters = if_not_else_linter()
)

lint(
  text = "if (!is.null(x)) x else 2",
  linters = if_not_else_linter()
)

Description

switch() statements in R are used to delegate behavior based on the value of some input scalar string, e.g. switch(x, a = 1, b = 3, c = 7, d = 8) will be one of 1, 3, 7, or 8, depending on the value of x.

Usage

if_switch_linter(max_branch_lines = 0L, max_branch_expressions = 0L)

Arguments

Details

This can also be accomplished by repeated if/⁠else⁠ statements like so: if (x == "a") 1 else if (x == "b") 2 else if (x == "c") 7 else 8 (implicitly, the last ⁠else⁠ assumes x only takes 4 possible values), but this is more cluttered and slower (note that switch() takes the same time to evaluate regardless of the value of x, and is faster even when x takes the first value (here a), and that the if/⁠else⁠ approach is roughly linear in the number of conditions that need to be evaluated, here up to 3 times).

Tags

best_practices, configurable, consistency, efficiency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "if (x == 'a') 1 else if (x == 'b') 2 else 3",
  linters = if_switch_linter()
)

code <- paste(
  "if (x == 'a') {",
  "  1",
  "} else if (x == 'b') {",
  "  2",
  "} else if (x == 'c') {",
  "  y <- x",
  "  z <- sqrt(match(y, letters))",
  "  z",
  "}",
  sep = "\n"
)
writeLines(code)
lint(
  text = code,
  linters = if_switch_linter()
)

code <- paste(
  "if (x == 'a') {",
  "  1",
  "} else if (x == 'b') {",
  "  2",
  "} else if (x == 'c') {",
  "  y <- x",
  "  z <- sqrt(",
  "    match(y, letters)",
  "  )",
  "  z",
  "}",
  sep = "\n"
)
writeLines(code)
lint(
  text = code,
  linters = if_switch_linter()
)

code <- paste(
  "switch(x,",
  "  a = {",
  "    1",
  "    2",
  "    3",
  "  },",
  "  b = {",
  "    1",
  "    2",
  "  }",
  ")",
  sep = "\n"
)
writeLines(code)
lint(
  text = code,
  linters = if_switch_linter(max_branch_lines = 2L)
)

# okay
lint(
  text = "switch(x, a = 1, b = 2, 3)",
  linters = if_switch_linter()
)

# switch() version not as clear
lint(
  text = "if (x == 'a') 1 else if (x == 'b' & y == 2) 2 else 3",
  linters = if_switch_linter()
)

code <- paste(
  "if (x == 'a') {",
  "  1",
  "} else if (x == 'b') {",
  "  2",
  "} else if (x == 'c') {",
  "  y <- x",
  "  z <- sqrt(match(y, letters))",
  "  z",
  "}",
  sep = "\n"
)
writeLines(code)
lint(
  text = code,
  linters = if_switch_linter(max_branch_lines = 2L)
)

code <- paste(
  "if (x == 'a') {",
  "  1",
  "} else if (x == 'b') {",
  "  2",
  "} else if (x == 'c') {",
  "  y <- x",
  "  z <- sqrt(",
  "    match(y, letters)",
  "  )",
  "  z",
  "}",
  sep = "\n"
)
writeLines(code)
lint(
  text = code,
  linters = if_switch_linter(max_branch_expressions = 2L)
)

code <- paste(
  "switch(x,",
  "  a = {",
  "    1",
  "    2",
  "    3",
  "  },",
  "  b = {",
  "    1",
  "    2",
  "  }",
  ")",
  sep = "\n"
)
writeLines(code)
lint(
  text = code,
  linters = if_switch_linter(max_branch_lines = 3L)
)

Description

ifelse(x > M, M, x) is the same as pmin(x, M), but harder to read and requires several passes over the vector.

Usage

ifelse_censor_linter()

Details

The same goes for other similar ways to censor a vector, e.g. ifelse(x <= M, x, M) is pmin(x, M), ifelse(x < m, m, x) is pmax(x, m), and ifelse(x >= m, x, m) is pmax(x, m).

Tags

best_practices, efficiency

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "ifelse(5:1 < pi, 5:1, pi)",
  linters = ifelse_censor_linter()
)

lint(
  text = "ifelse(x > 0, x, 0)",
  linters = ifelse_censor_linter()
)

# okay
lint(
  text = "pmin(5:1, pi)",
  linters = ifelse_censor_linter()
)

lint(
  text = "pmax(x, 0)",
  linters = ifelse_censor_linter()
)

Description

Assigning inside function calls makes the code difficult to read, and should be avoided, except for functions that capture side-effects (e.g. capture.output()).

Usage

implicit_assignment_linter(
  except = c("bquote", "expression", "expr", "quo", "quos", "quote"),
  allow_lazy = FALSE,
  allow_scoped = FALSE
)

Arguments

Tags

best_practices, configurable, readability, style

See Also

• linters for a complete list of linters available in lintr.

• https://style.tidyverse.org/syntax.html#assignment

Examples

# will produce lints
lint(
  text = "if (x <- 1L) TRUE",
  linters = implicit_assignment_linter()
)

lint(
  text = "mean(x <- 1:4)",
  linters = implicit_assignment_linter()
)

# okay
lines <- "x <- 1L\nif (x) TRUE"
writeLines(lines)
lint(
  text = lines,
  linters = implicit_assignment_linter()
)

lines <- "x <- 1:4\nmean(x)"
writeLines(lines)
lint(
  text = lines,
  linters = implicit_assignment_linter()
)

lint(
  text = "A && (B <- foo(A))",
  linters = implicit_assignment_linter(allow_lazy = TRUE)
)

lines <- c(
  "if (any(idx <- x < 0)) {",
  "  stop('negative elements: ', toString(which(idx)))",
  "}"
)
writeLines(lines)
lint(
  text = lines,
  linters = implicit_assignment_linter(allow_scoped = TRUE)
)

Description

Check that integers are explicitly typed using the form 1L instead of 1.

Usage

implicit_integer_linter(allow_colon = FALSE)

Arguments

Tags

best_practices, configurable, consistency, style

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "x <- 1",
  linters = implicit_integer_linter()
)

lint(
  text = "x[2]",
  linters = implicit_integer_linter()
)

lint(
  text = "1:10",
  linters = implicit_integer_linter()
)

# okay
lint(
  text = "x <- 1.0",
  linters = implicit_integer_linter()
)

lint(
  text = "x <- 1L",
  linters = implicit_integer_linter()
)

lint(
  text = "x[2L]",
  linters = implicit_integer_linter()
)

lint(
  text = "1:10",
  linters = implicit_integer_linter(allow_colon = TRUE)
)

Description

Check that indentation is consistent

Usage

indentation_linter(
  indent = 2L,
  hanging_indent_style = c("tidy", "always", "never"),
  assignment_as_infix = TRUE
)

Arguments

# complies to any style
map(
  x,
  f,
  additional_arg = 42
)

# complies to "tidy" and "never"
map(x, f,
  additional_arg = 42
)

# complies to "always"
map(x, f,
    additional_arg = 42
)

# complies to "tidy" and "always"
map(x, f,
    additional_arg = 42)

# complies to "never"
map(x, f,
  additional_arg = 42)

# complies to "tidy"
function(
    a,
    b) {
  # body
}

# complies to any style
variable <- a %+%
  b %+%
  c

# complies to assignment_as_infix = TRUE
variable <-
  a %+%
  b %+%
  c

# complies to assignment_as_infix = FALSE
variable <-
  a %+%
    b %+%
    c

Tags

configurable, default, readability, style

See Also

• linters for a complete list of linters available in lintr.

• https://style.tidyverse.org/syntax.html#indenting

• https://style.tidyverse.org/functions.html#long-lines-1

Examples

# will produce lints
code_lines <- "if (TRUE) {\n1 + 1\n}"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = indentation_linter()
)

code_lines <- "if (TRUE) {\n    1 + 1\n}"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = indentation_linter()
)

code_lines <- "map(x, f,\n  additional_arg = 42\n)"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = indentation_linter(hanging_indent_style = "always")
)

code_lines <- "map(x, f,\n    additional_arg = 42)"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = indentation_linter(hanging_indent_style = "never")
)

# okay
code_lines <- "map(x, f,\n  additional_arg = 42\n)"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = indentation_linter()
)

code_lines <- "if (TRUE) {\n    1 + 1\n}"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = indentation_linter(indent = 4)
)

Description

Check that infix operators are surrounded by spaces. Enforces the corresponding Tidyverse style guide rule; see https://style.tidyverse.org/syntax.html#infix-operators.

Usage

infix_spaces_linter(exclude_operators = NULL, allow_multiple_spaces = TRUE)

Arguments

Tags

configurable, default, readability, style

See Also

• linters for a complete list of linters available in lintr.

• https://style.tidyverse.org/syntax.html#infix-operators

Examples

# will produce lints
lint(
  text = "x<-1L",
  linters = infix_spaces_linter()
)

lint(
  text = "1:4 %>%sum()",
  linters = infix_spaces_linter()
)

# okay
lint(
  text = "x <- 1L",
  linters = infix_spaces_linter()
)

lint(
  text = "1:4 %>% sum()",
  linters = infix_spaces_linter()
)

code_lines <- "
ab     <- 1L
abcdef <- 2L
"
writeLines(code_lines)
lint(
  text = code_lines,
  linters = infix_spaces_linter(allow_multiple_spaces = TRUE)
)

lint(
  text = "a||b",
  linters = infix_spaces_linter(exclude_operators = "||")
)

lint(
  text = "sum(1:10, na.rm=TRUE)",
  linters = infix_spaces_linter(exclude_operators = "EQ_SUB")
)

Description

as.Date(c(a, b)) is logically equivalent to c(as.Date(a), as.Date(b)). The same equivalence holds for several other vectorized functions like as.POSIXct() and math functions like sin(). The former is to be preferred so that the most expensive part of the operation (as.Date()) is applied only once.

Usage

inner_combine_linter()

Details

Note that strptime() has one idiosyncrasy to be aware of, namely that auto-detected ⁠format=⁠ is set by the first matching input, which means that a case like c(as.POSIXct("2024-01-01"), as.POSIXct("2024-01-01 01:02:03")) gives different results to as.POSIXct(c("2024-01-01", "2024-01-01 01:02:03")). This false positive is rare; a workaround where possible is to use consistent formatting, i.e., "2024-01-01 00:00:00" in the example.

Tags

consistency, efficiency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "c(log10(x), log10(y), log10(z))",
  linters = inner_combine_linter()
)

# okay
lint(
  text = "log10(c(x, y, z))",
  linters = inner_combine_linter()
)

lint(
  text = "c(log(x, base = 10), log10(x, base = 2))",
  linters = inner_combine_linter()
)

Description

Helper for determining whether the current source_expression contains all expressions in the current file, or just a single expression.

Usage

is_lint_level(source_expression, level = c("expression", "file"))

Arguments

Examples

tmp <- tempfile()
writeLines(c("x <- 1", "y <- x + 1"), tmp)
source_exprs <- get_source_expressions(tmp)
is_lint_level(source_exprs$expressions[[1L]], level = "expression")
is_lint_level(source_exprs$expressions[[1L]], level = "file")
is_lint_level(source_exprs$expressions[[3L]], level = "expression")
is_lint_level(source_exprs$expressions[[3L]], level = "file")
unlink(tmp)

Description

is.numeric() returns TRUE when typeof(x) is double or integer – testing is.numeric(x) || is.integer(x) is thus redundant.

Usage

is_numeric_linter()

Details

NB: This linter plays well with class_equals_linter(), which can help avoid further is.numeric() equivalents like any(class(x) == c("numeric", "integer")).

Tags

best_practices, consistency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "is.numeric(y) || is.integer(y)",
  linters = is_numeric_linter()
)

lint(
  text = 'class(z) %in% c("numeric", "integer")',
  linters = is_numeric_linter()
)

# okay
lint(
  text = "is.numeric(y) || is.factor(y)",
  linters = is_numeric_linter()
)

lint(
  text = 'class(z) %in% c("numeric", "integer", "factor")',
  linters = is_numeric_linter()
)

Description

Any valid symbol can be used as a keyword argument to an R function call. Sometimes, it is necessary to quote (or backtick) an argument that is not an otherwise valid symbol (e.g. creating a vector whose names have spaces); besides this edge case, quoting should not be done.

Usage

keyword_quote_linter()

Details

The most common source of violation for this is creating named vectors, lists, or data.frame-alikes, but it can be observed in other calls as well.

Similar reasoning applies to extractions with $ or @.

Tags

consistency, readability, style

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = 'data.frame("a" = 1)',
  linters = keyword_quote_linter()
)

lint(
  text = "data.frame(`a` = 1)",
  linters = keyword_quote_linter()
)

lint(
  text = 'my_list$"key"',
  linters = keyword_quote_linter()
)

lint(
  text = 's4obj@"key"',
  linters = keyword_quote_linter()
)

# okay
lint(
  text = "data.frame(`a b` = 1)",
  linters = keyword_quote_linter()
)

lint(
  text = "my_list$`a b`",
  linters = keyword_quote_linter()
)

Description

length(levels(x)) is the same as nlevels(x), but harder to read.

Usage

length_levels_linter()

Tags

best_practices, consistency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "length(levels(x))",
  linters = length_levels_linter()
)

# okay
lint(
  text = "length(c(levels(x), levels(y)))",
  linters = length_levels_linter()
)

Description

Usage like length(x == 0) is a mistake. If you intended to check x is empty, use length(x) == 0. Other mistakes are possible, but running length() on the outcome of a logical comparison is never the best choice.

Usage

length_test_linter()

Tags

best_practices, consistency, robustness

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "length(x == 0)",
  linters = length_test_linter()
)

# okay
lint(
  text = "length(x) > 0",
  linters = length_test_linter()
)

Description

lengths() is a function that was added to base R in version 3.2.0 to get the length of each element of a list. It is equivalent to sapply(x, length), but faster and more readable.

Usage

lengths_linter()

Tags

best_practices, efficiency, readability

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints
lint(
  text = "sapply(x, length)",
  linters = lengths_linter()
)

lint(
  text = "vapply(x, length, integer(1L))",
  linters = lengths_linter()
)

lint(
  text = "purrr::map_int(x, length)",
  linters = lengths_linter()
)

# okay
lint(
  text = "lengths(x)",
  linters = lengths_linter()
)

Description

This linter covers several rules related to library() calls:

Usage

library_call_linter(allow_preamble = TRUE)

Arguments

Details

• Enforce such calls to all be at the top of the script.

• Block usage of argument character.only, in particular for loading packages in a loop.

• Block consecutive calls to suppressMessages(library(.)) in favor of using suppressMessages() only once to suppress messages from all library() calls. Ditto suppressPackageStartupMessages().

Tags

best_practices, configurable, readability, style

See Also

linters for a complete list of linters available in lintr.

Examples

# will produce lints

code <- "library(dplyr)\nprint('test')\nlibrary(tidyr)"
writeLines(code)
lint(
  text = code,
  linters = library_call_linter()
)

lint(
  text = "library('dplyr', character.only = TRUE)",
  linters = library_call_linter()
)

code <- paste(
  "pkg <- c('dplyr', 'tibble')",
  "sapply(pkg, library, character.only = TRUE)",
  sep = "\n"
)
writeLines(code)
lint(
  text = code,
  linters = library_call_linter()
)

code <- "suppressMessages(library(dplyr))\nsuppressMessages(library(tidyr))"
writeLines(code)
lint(
  text = code,
  linters = library_call_linter()
)

# okay
code <- "library(dplyr)\nprint('test')"
writeLines(code)
lint(
  text = code,
  linters = library_call_linter()
)

code <- "# comment\nlibrary(dplyr)"
lint(
  text = code,
  linters = library_call_linter()
)

code <- paste(
  "foo <- function(pkg) {",
  "  sapply(pkg, library, character.only = TRUE)",
  "}",
  sep = "\n"
)
writeLines(code)
lint(
  text = code,
  linters = library_call_linter()
)

code <- "suppressMessages({\n  library(dplyr)\n  library(tidyr)\n})"
writeLines(code)
lint(
  text = code,
  linters = library_call_linter()
)

Description

Check that the line length of both comments and code is less than length.

Usage

line_length_linter(length = 80L)

Arguments

Tags

configurable, default, readability, style

See Also

• linters for a complete list of linters available in lintr.

• https://style.tidyverse.org/syntax.html#long-lines

Examples

# will produce lints
lint(
  text = strrep("x", 23L),
  linters = line_length_linter(length = 20L)
)

# okay
lint(
  text = strrep("x", 21L),
  linters = line_length_linter(length = 40L)
)

Description

• lint() lints a single file.

• lint_dir() lints all files in a directory.

• lint_package() lints all likely locations for R files in a package, i.e. ⁠R/⁠, ⁠tests/⁠, ⁠inst/⁠, ⁠vignettes/⁠, ⁠data-raw/⁠, ⁠demo/⁠, and ⁠exec/⁠.

Usage

lint(
  filename,
  linters = NULL,
  ...,
  cache = FALSE,
  parse_settings = TRUE,
  text = NULL
)

lint_dir(
  path = ".",
  ...,
  relative_path = TRUE,
  exclusions = list("renv", "packrat"),
  pattern = "(?i)[.](r|rmd|qmd|rnw|rhtml|rrst|rtex|rtxt)$",
  parse_settings = TRUE,
  show_progress = NULL
)

lint_package(
  path = ".",
  ...,
  relative_path = TRUE,
  exclusions = list("R/RcppExports.R"),
  parse_settings = TRUE,
  show_progress = NULL
)

Arguments

Details

Read vignette("lintr") to learn how to configure which linters are run by default. Note that if files contain unparseable encoding problems, only the encoding problem will be linted to avoid unintelligible error messages from other linters.

Value

An object of class c("lints", "list"), each element of which is a "list" object.

Examples

# linting inline-code
lint("a = 123\n")
lint(text = "a = 123")

# linting a file
f <- tempfile()
writeLines("a=1", f)
lint(f)
unlink(f)

if (FALSE) {
  lint_dir()

  lint_dir(
    linters = list(semicolon_linter()),
    exclusions = list(
      "inst/doc/creating_linters.R" = 1,
      "inst/example/bad.R",
      "renv"
    )
  )
}
if (FALSE) {
  lint_package()

  lint_package(
    linters = linters_with_defaults(semicolon_linter = semicolon_linter()),
    exclusions = list("inst/doc/creating_linters.R" = 1, "inst/example/bad.R")
  )
}

Description

Create a lint object

Usage

Lint(
  filename,
  line_number = 1L,
  column_number = 1L,
  type = c("style", "warning", "error"),
  message = "",
  line = "",
  ranges = NULL,
  linter = ""
)

Arguments

Value

an object of class c("lint", "list").

Description

Create a linter closure

Usage

Linter(
  fun,
  name = linter_auto_name(),
  linter_level = c(NA_character_, "file", "expression")
)

Arguments

Value

The same function with its class set to 'linter'.

Description

A variety of linters are available in lintr. The most popular ones are readily accessible through default_linters().

Within a lint() function call, the linters in use are initialized with the provided arguments and fed with the source file (provided by get_source_expressions()).

A data frame of all available linters can be retrieved using available_linters(). Documentation for linters is structured into tags to allow for easier discovery; see also available_tags().

Tags

The following tags exist:

• best_practices (63 linters)

• common_mistakes (11 linters)

• configurable (44 linters)

• consistency (32 linters)

• correctness (7 linters)

• default (25 linters)

• deprecated (6 linters)

• efficiency (29 linters)

• executing (6 linters)

• package_development (14 linters)

• pkg_testthat (12 linters)

• readability (64 linters)

• regex (4 linters)

• robustness (17 linters)

• style (40 linters)

• tidy_design (1 linters)

Linters

The following linters exist:

• absolute_path_linter (tags: best_practices, configurable, robustness)

• any_duplicated_linter (tags: best_practices, efficiency)

• any_is_na_linter (tags: best_practices, efficiency)

• assignment_linter (tags: configurable, consistency, default, style)

• backport_linter (tags: configurable, package_development, robustness)

• boolean_arithmetic_linter (tags: best_practices, efficiency, readability)

• brace_linter (tags: configurable, default, readability, style)

• class_equals_linter (tags: best_practices, consistency, robustness)

• commas_linter (tags: configurable, default, readability, style)

• commented_code_linter (tags: best_practices, default, readability, style)

• comparison_negation_linter (tags: consistency, readability)

• condition_call_linter (tags: best_practices, configurable, style, tidy_design)

• condition_message_linter (tags: best_practices, consistency)

• conjunct_test_linter (tags: best_practices, configurable, package_development, pkg_testthat, readability)

• consecutive_assertion_linter (tags: consistency, readability, style)

• consecutive_mutate_linter (tags: configurable, consistency, efficiency, readability)

• cyclocomp_linter (tags: best_practices, configurable, readability, style)

• duplicate_argument_linter (tags: common_mistakes, configurable, correctness)

• empty_assignment_linter (tags: best_practices, readability)

• equals_na_linter (tags: common_mistakes, correctness, default, robustness)

• expect_comparison_linter (tags: best_practices, package_development, pkg_testthat)

• expect_identical_linter (tags: package_development, pkg_testthat)

• expect_length_linter (tags: best_practices, package_development, pkg_testthat, readability)

• expect_named_linter (tags: best_practices, package_development, pkg_testthat, readability)

• expect_not_linter (tags: best_practices, package_development, pkg_testthat, readability)

• expect_null_linter (tags: best_practices, package_development, pkg_testthat)

• expect_s3_class_linter (tags: best_practices, package_development, pkg_testthat)

• expect_s4_class_linter (tags: best_practices, package_development, pkg_testthat)

• expect_true_false_linter (tags: best_practices, package_development, pkg_testthat, readability)

• expect_type_linter (tags: best_practices, package_development, pkg_testthat)

• fixed_regex_linter (tags: best_practices, configurable, efficiency, readability, regex)

• for_loop_index_linter (tags: best_practices, readability, robustness)

• function_argument_linter (tags: best_practices, consistency, style)

• function_left_parentheses_linter (tags: default, readability, style)

• function_return_linter (tags: best_practices, readability)

• if_not_else_linter (tags: configurable, consistency, readability)

• if_switch_linter (tags: best_practices, configurable, consistency, efficiency, readability)

• ifelse_censor_linter (tags: best_practices, efficiency)

• implicit_assignment_linter (tags: best_practices, configurable, readability, style)

• implicit_integer_linter (tags: best_practices, configurable, consistency, style)

• indentation_linter (tags: configurable, default, readability, style)

• infix_spaces_linter (tags: configurable, default, readability, style)

• inner_combine_linter (tags: consistency, efficiency, readability)

• is_numeric_linter (tags: best_practices, consistency, readability)

• keyword_quote_linter (tags: consistency, readability, style)

• length_levels_linter (tags: best_practices, consistency, readability)

• length_test_linter (tags: common_mistakes, efficiency)

• lengths_linter (tags: best_practices, efficiency, readability)

• library_call_linter (tags: best_practices, configurable, readability, style)

• line_length_linter (tags: configurable, default, readability, style)

• list_comparison_linter (tags: best_practices, common_mistakes)

• literal_coercion_linter (tags: best_practices, consistency, efficiency)

• matrix_apply_linter (tags: efficiency, readability)

• missing_argument_linter (tags: common_mistakes, configurable, correctness)

• missing_package_linter (tags: common_mistakes, robustness)

• namespace_linter (tags: configurable, correctness, executing, robustness)

• nested_ifelse_linter (tags: efficiency, readability)

• nested_pipe_linter (tags: configurable, consistency, readability)

• nonportable_path_linter (tags: best_practices, configurable, robustness)

• nrow_subset_linter (tags: best_practices, consistency, efficiency)

• numeric_leading_zero_linter (tags: consistency, readability, style)

• nzchar_linter (tags: best_practices, consistency, efficiency)

• object_length_linter (tags: configurable, default, executing, readability, style)

• object_name_linter (tags: configurable, consistency, default, executing, style)

• object_overwrite_linter (tags: best_practices, configurable, executing, readability, robustness)

• object_usage_linter (tags: configurable, correctness, default, executing, readability, style)

• one_call_pipe_linter (tags: readability, style)

• outer_negation_linter (tags: best_practices, efficiency, readability)

• package_hooks_linter (tags: correctness, package_development, style)

• paren_body_linter (tags: default, readability, style)

• paste_linter (tags: best_practices, configurable, consistency)

• pipe_call_linter (tags: readability, style)

• pipe_consistency_linter (tags: configurable, readability, style)

• pipe_continuation_linter (tags: default, readability, style)

• pipe_return_linter (tags: best_practices, common_mistakes)

• print_linter (tags: best_practices, consistency)

• quotes_linter (tags: configurable, consistency, default, readability, style)

• redundant_equals_linter (tags: best_practices, common_mistakes, efficiency, readability)

• redundant_ifelse_linter (tags: best_practices, configurable, consistency, efficiency)

• regex_subset_linter (tags: best_practices, efficiency, regex)

• rep_len_linter (tags: best_practices, consistency, readability)

• repeat_linter (tags: readability, style)

• return_linter (tags: configurable, default, style)

• routine_registration_linter (tags: best_practices, efficiency, robustness)

• sample_int_linter (tags: efficiency, readability, robustness)

• scalar_in_linter (tags: best_practices, configurable, consistency, efficiency, readability)

• semicolon_linter (tags: configurable, default, readability, style)

• seq_linter (tags: best_practices, consistency, default, efficiency, robustness)

• sort_linter (tags: best_practices, efficiency, readability)

• spaces_inside_linter (tags: default, readability, style)

• spaces_left_parentheses_linter (tags: default, readability, style)

• sprintf_linter (tags: common_mistakes, correctness)

• stopifnot_all_linter (tags: best_practices, readability)

• string_boundary_linter (tags: configurable, efficiency, readability, regex)

• strings_as_factors_linter (tags: robustness)

• system_file_linter (tags: best_practices, consistency, readability)

• T_and_F_symbol_linter (tags: best_practices, consistency, default, readability, robustness, style)

• terminal_close_linter (tags: best_practices, robustness)

• todo_comment_linter (tags: configurable, style)

• trailing_blank_lines_linter (tags: default, style)

• trailing_whitespace_linter (tags: configurable, default, style)

• undesirable_function_linter (tags: best_practices, configurable, robustness, style)

• undesirable_operator_linter (tags: best_practices, configurable, robustness, style)

• unnecessary_concatenation_linter (tags: configurable, efficiency, readability, style)

• unnecessary_lambda_linter (tags: best_practices, configurable, efficiency, readability)

• unnecessary_nesting_linter (tags: best_practices, configurable, consistency, readability)

• unnecessary_placeholder_linter (tags: best_practices, readability)

• unreachable_code_linter (tags: best_practices, configurable, readability)

• unused_import_linter (tags: best_practices, common_mistakes, configurable, executing)

• vector_logic_linter (tags: best_practices, common_mistakes, default, efficiency)

• which_grepl_linter (tags: consistency, efficiency, readability, regex)

• whitespace_linter (tags: consistency, default, style)

• yoda_test_linter (tags: best_practices, package_development, pkg_testthat, readability)