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Re-convert character columns in existing data frame

Source: R/type_convert.R
type_convert.Rd

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(),
  guess_integer = FALSE,
  guess_max = NA,
  verbose = FALSE
)

Arguments

df

A data frame.

col_types

One of NULL, a cols() specification, or a string.

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 (ASCII spaces and tabs) 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.

guess_integer

If TRUE, guess integer types for whole numbers, if FALSE guess numeric type for all numbers.

guess_max

Maximum number of data rows to use for guessing column types. NA: uses all data.

verbose

whether to print messages

Value

A data frame

Note

type_convert() removes a 'spec' attribute (if it presents).

Examples

df <- data.frame(
  x = as.character(runif(10)),
  y = as.character(sample(10)),
  stringsAsFactors = FALSE
)
str(df)
#> 'data.frame':	10 obs. of  2 variables:
#>  $ x: chr  "0.0807501375675201" "0.834333037259057" "0.600760886212811" "0.157208441523835" ...
#>  $ y: chr  "6" "9" "5" "8" ...
str(type_convert(df))
#> 'data.frame':	10 obs. of  2 variables:
#>  $ x: num  0.0808 0.8343 0.6008 0.1572 0.0074 ...
#>  $ y: num  6 9 5 8 7 2 10 3 1 4

df <- data.frame(x = c("NA", "10"), stringsAsFactors = FALSE)
str(type_convert(df))
#> 'data.frame':	2 obs. of  1 variable:
#>  $ x: num  NA 10