Package 'cereal'

Convert a JSON-serialized prototype to a vctrs prototype

Description

Create a vctrs::vec_ptype() from a JSON-serialized prototype created with cereal_encode().

Usage

cereal_decode(x)

Arguments

x	An object with class "cereal_*", such as "cereal_integer" or "cereal_factor"

Value

A vector of zero length, such as integer() or vctrs::new_factor()

Examples

cereal_decode(structure(list(), class = "cereal_integer"))
cereal_decode(structure(list(), class = "cereal_Date"))

---

Find needed details for vctrs prototype

Description

Find needed details for vctrs prototype

Usage

cereal_details(x)

Arguments

x

A vector

Value

A list

Examples

cereal_details(factor(letters[1:5], labels = "letter"))
cereal_details(factor(LETTERS[3:1], ordered = TRUE))
cereal_details(as.POSIXct("2023-01-01", tz = "America/New_York"))

---

Encode a vector as JSON

Description

Create a list encoding the vctrs prototype (metadata) that can be stored as JSON.

Usage

cereal_encode(x)

Arguments

x

A vector

Details

Use the digits option to specify how many digits after the decimal point to record in JSON, for example via withr::local_options().

Value

A list that can be converted to JSON with jsonlite::toJSON()

See Also

vctrs::vec_ptype(), cereal_decode()

Examples

cereal_encode(1:10)
cereal_encode(Sys.Date())
cereal_encode(sample(letters, 5))
cereal_encode(factor(letters[1:5], labels = "letter"))
cereal_encode(factor(LETTERS[3:1], ordered = TRUE))

## you can encode a ptype as well:
ptype <- vctrs::vec_ptype(factor(LETTERS[3:1], ordered = TRUE))
## but "example" is NULL:
cereal_encode(ptype)

---

Serialize and deserialize the prototype of a data frame to JSON

Description

The function cereal_to_json() serializes the vctrs prototype of a data frame to JSON, and the function cereal_from_json() deserializes from a JSON prototype back to a vctrs prototype.

Usage

cereal_to_json(data)

cereal_from_json(x)

Arguments

data	A data frame
x	A JSON string

Value

cereal_to_json() returns a JSON string like jsonlite::toJSON(), and cereal_from_json() returns a vctrs ptype, like vctrs::vec_ptype().

See Also

cereal_encode(), cereal_decode()

Examples

df <- tibble::tibble(
    a = 1,
    b = 2L,
    c = Sys.Date(),
    d = as.POSIXct("2019-01-01", tz = "America/New_York"),
    e = "x",
    f = factor("blue", levels = c("blue", "green", "red")),
    g = ordered("small", levels = c("small", "medium", "large"))
)

json <- cereal_to_json(df)
json

str(cereal_from_json(json))
## same as:
str(vctrs::vec_ptype(df))

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