readr: type_convert – R documentation

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type_convert

Re-convert character columns in existing data frame

Description

This is useful if you need to do some manual munging - you can read the columns in as character, clean it up with (e.g.) regular expressions and then let readr take another stab at parsing it. The name is a homage to the base utils::type.convert().

Usage

type_convert(
  df,
  col_types = NULL,
  na = c("", "NA"),
  trim_ws = TRUE,
  locale = default_locale()
)

Arguments

`df`	A data frame.
`col_types`	One of `NULL`, a `cols()` specification, or a string. See `vignette("readr")` for more details. If `NULL`, column types will be imputed using all rows.
`na`	Character vector of strings to interpret as missing values. Set this option to `character()` to indicate no missing values.
`trim_ws`	Should leading and trailing whitespace be trimmed from each field before parsing it?
`locale`	The locale controls defaults that vary from place to place. The default locale is US-centric (like R), but you can use `locale()` to create your own locale that controls things like the default time zone, encoding, decimal mark, big mark, and day/month names.

Note

type_convert() removes a 'spec' attribute, because it likely modifies the column data types. (see spec() for more information about column specifications).

Examples

df <- data.frame(
  x = as.character(runif(10)),
  y = as.character(sample(10)),
  stringsAsFactors = FALSE
)
str(df)
str(type_convert(df))

df <- data.frame(x = c("NA", "10"), stringsAsFactors = FALSE)
str(type_convert(df))

# Type convert can be used to infer types from an entire dataset

# first read the data as character
data <- read_csv(readr_example("mtcars.csv"),
                 col_types = cols(.default = col_character()))
str(data)
# Then convert it with type_convert
type_convert(data)

readr

Read Rectangular Text Data

v1.4.0

GPL (>= 2) | file LICENSE

Authors

Hadley Wickham [aut], Jim Hester [aut, cre], Romain Francois [ctb], R Core Team [ctb] (Date time code adapted from R), RStudio [cph, fnd], Jukka Jylänki [ctb, cph] (grisu3 implementation), Mikkel Jørgensen [ctb, cph] (grisu3 implementation)

Initial release