strcoll: Compare Strings

In stringx: Replacements for Base String Functions Powered by 'stringi'

Compare Strings

Description

These functions provide means to compare strings in any locale using the Unicode collation algorithm.

Usage

strcoll(
  e1,
  e2,
  locale = NULL,
  strength = 3L,
  alternate_shifted = FALSE,
  french = FALSE,
  uppercase_first = NA,
  case_level = FALSE,
  normalisation = FALSE,
  numeric = FALSE
)

e1 %x<% e2

e1 %x<=% e2

e1 %x==% e2

e1 %x!=% e2

e1 %x>% e2

e1 %x>=% e2

Arguments

e1, e2	character vector whose corresponding elements are to be compared
locale	NULL or "" for the default locale (see stri_locale_get) or a single string with a locale identifier, see stri_locale_list
strength	see stri_opts_collator
alternate_shifted	see stri_opts_collator
french	see stri_opts_collator
uppercase_first	see stri_opts_collator
case_level	see stri_opts_collator
normalisation	see stri_opts_collator
numeric	see stri_opts_collator

Details

These functions are fully vectorised with respect to both arguments.

For a locale-insensitive behaviour like that of strcmp from the standard C library, call strcoll(e1, e2, locale="C", strength=4L, normalisation=FALSE). However, some normalisation will still be performed.

Value

strcoll returns an integer vector representing the comparison results: if a string in e1 is smaller than the corresponding string in e2, the corresponding result will be equal to -1, and 0 if they are canonically equivalent, as well as 1 if the former is greater than the latter.

The binary operators call strcoll with default arguments and return logical vectors.

Differences from Base R

Replacements for base Comparison operators implemented with stri_cmp.

• collation in different locales is difficult and non-portable across platforms [fixed here – using services provided by ICU]

• overloading `<.character` has no effect in R, because S3 method dispatch is done internally with hard-coded support for character arguments. We could have replaced the generic `<` with the one that calls UseMethod, but it feels like a too intrusive solution [fixed by introducing the `%x<%` operator]

Author(s)

Marek Gagolewski

See Also

The official online manual of stringx at https://stringx.gagolewski.com/

Related function(s): xtfrm

Examples

# lexicographic vs. numeric sort
strcoll("100", c("1", "10", "11", "99", "100", "101", "1000"))
strcoll("100", c("1", "10", "11", "99", "100", "101", "1000"), numeric=TRUE)
strcoll("hladn\u00FD", "chladn\u00FD", locale="sk_SK")

stringx documentation built on April 3, 2025, 6:17 p.m.