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Separate a character column into multiple columns in a column of nested data frames

Source: R/nest_separate.R
nest_separate.Rd

nest_separate() is used to separate a single character column into multiple columns using a regular expression or a vector of character positions in a list of nested data frames.

Usage

nest_separate(
  .data,
  .nest_data,
  col,
  into,
  sep = "[^[:alnum:]]+",
  remove = TRUE,
  convert = FALSE,
  extra = "warn",
  fill = "warn",
  ...
)

Arguments

.data

A data frame, data frame extension (e.g., a tibble), or a lazy data frame (e.g., from dbplyr or dtplyr).

.nest_data

A list-column containing data frames

col

Column name or position within. Must be present in all data frames in .nest_data. This is passed to tidyselect::vars_pull().

This argument is passed by expression and supports quasiquotation (you can unquote column names or column positions).

into

Names of new variables to create as character vector. Use NA to omit the variable in the output.

sep

Separator between columns.

If character, sep is interpreted as a regular expression. The default value is a regular expression that matches any sequence of non-alphanumeric values.

If numeric, sep is interpreted as character positions to split at. Positive values start at 1 at the far-left of the string; negative value start at -1 at the far-right of the string. The length of sep should be one less than into.

remove

If TRUE, remove input column from output data frame.

convert

If TRUE, will run type.convert() with as.is = TRUE on new columns. This is useful if the component columns are integer, numeric or logical.

NB: this will cause string "NA"s to be converted to NAs.

extra

If sep is a character vector, this controls what happens when there are too many pieces. There are three valid options:

  • "warn" (the default): emit a warning and drop extra values.

  • "drop": drop any extra values without a warning.

  • "merge": only splits at most length(into) times

fill

If sep is a character vector, this controls what happens when there are not enough pieces. There are three valid options:

  • "warn" (the default): emit a warning and fill from the right

  • "right": fill with missing values on the right

  • "left": fill with missing values on the left

...

Additional arguments passed on to tidyr::separate() methods.

Value

An object of the same type as .data. Each object in the column .nest_data will have the specified column split according to the regular expression or the vector of character positions.

Details

nest_separate() is a wrapper for tidyr::separate() and maintains the functionality of separate() within each nested data frame. For more information on separate() please refer to the documentation in 'tidyr'.

See also

Other tidyr verbs: nest_drop_na(), nest_extract(), nest_fill(), nest_replace_na(), nest_unite()

Examples

set.seed(123)
gm <- 
  gapminder::gapminder %>% 
  dplyr::mutate(comb = paste(continent, year, sep = "-"))
  
gm_nest <- gm %>% tidyr::nest(country_data = -continent)

gm_nest %>% 
  nest_separate(country_data,
                col = comb,
                into = c("var1","var2"),
                sep = "-")
#> # A tibble: 5 × 2
#>   continent country_data      
#>   <fct>     <list>            
#> 1 Asia      <tibble [396 × 7]>
#> 2 Europe    <tibble [360 × 7]>
#> 3 Africa    <tibble [624 × 7]>
#> 4 Americas  <tibble [300 × 7]>
#> 5 Oceania   <tibble [24 × 7]>