Standardise labels

This function standardises labels e.g. used as variable names or character string values, removing non-ascii characters, replacing diacritics (e.g. é, ô) with their closest ascii equivalents, and standardises separating characters. See details for more information on label transformation.

clean_labels(x, sep = "_", transformation = "Any-Latin; Latin-ASCII",
  protect = "")

Arguments

x

A vector of labels, normally provided as characters.
sep

A character string used as separator, defaulting to '_'.
transformation

a string to be passed on to stringi::stri_trans_general() for conversion. Default is "Any-Latin; Latin-ASCII", which will convert any non-latin characters to latin and then converts all accented characters to ASCII characters. See stringi::stri_trans_list() for a full list of options.
protect

a character string defining the punctuation that should be protected. This helps prevent meaninful symbols like > and < from being removed.

Details

The following changes are performed:

  • all non-ascii characters are removed

  • all diacritics are replaced with their non-accentuated equivalents, e.g. 'é', 'ê' and 'è' become 'e'.

  • all characters are set to lower case

  • separators are standardised to the use of a single character provided in sep (defaults to '_'); heading and trailing separators are removed.

Note

Because of differences between the underlying transliteration engine (ICU), the default transformations will not transilierate German umlaute correctly. You can add them by specifying "de-ASCII" in the transformation string after "Any-Latin".

Examples


clean_labels("-_-This is; A    WeÏrD**./sêntënce...")
#> [1] "this_is_a_weird_sentence"
clean_labels("-_-This is; A    WeÏrD**./sêntënce...", sep = ".")
#> [1] "this.is.a.weird.sentence"
input <- c("ますだ, よしひこ", "Peter and stëven", "peter-and.stëven", "pëtêr and stëven  _-")
input
#> [1] "ますだ, よしひこ"     "Peter and stëven"     "peter-and.stëven"    
#> [4] "pëtêr and stëven  _-"
clean_labels(input)
#> [1] "masuda_yoshihiko" "peter_and_steven" "peter_and_steven" "peter_and_steven"

# Don't transliterate non-latin words
clean_labels(input, transformation = "Latin-ASCII")
#> [1] "ますだ_よしひこ"  "peter_and_steven" "peter_and_steven" "peter_and_steven"

# protect useful symbols
clean_labels(c("energy > 9000", "energy < 9000"), protect = "><")
#> [1] "energy_>_9000" "energy_<_9000"

# if you only want to clean accents, transform to lower, and transliterate,
# you can specify "[:punct:][:space:]" for protect:
clean_labels(input, protect = "[:punct:][:space:]")
#> [1] "masuda, yoshihiko"    "peter and steven"     "peter-and.steven"    
#> [4] "peter and steven  _-"

# appropriately transliterate Germanic umlaute
if (stringi::stri_info()$ICU.system) {
  # This will only be true if you have the correct version of ICU installed

  clean_labels("'é', 'ê' and 'è' become 'e', 'ö' becomes 'oe', etc.",
               transformation = "Any-Latin; de-ASCII; Latin-ASCII")
}
#> [1] "e_e_and_e_become_e_oe_becomes_oe_etc"