stri_opts_collator: Generate a List with Collator Settings
In stringi: Character String Processing Facilities

Description Usage Arguments Details Value References See Also Examples

A convenience function to tune the ICU Collator's behavior, e.g., in stri_compare, stri_order, stri_unique, stri_duplicated, as well as stri_detect_coll and other stringi-search-coll functions.

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stri_opts_collator(locale = NULL, strength = 3L,
  alternate_shifted = FALSE, french = FALSE, uppercase_first = NA,
  case_level = FALSE, normalization = FALSE, numeric = FALSE, ...)

`locale`	single string, `NULL` or `""` for default locale
`strength`	single integer in {1,2,3,4}, which defines collation strength; `1` for the most permissive collation rules, `4` for the most strict ones
`alternate_shifted`	single logical value; `FALSE` treats all the code points with non-ignorable primary weights in the same way, `TRUE` causes code points with primary weights that are equal or below the variable top value to be ignored on primary level and moved to the quaternary level
`french`	single logical value; used in Canadian French; `TRUE` results in secondary weights being considered backwards
`uppercase_first`	single logical value; `NA` orders upper and lower case letters in accordance to their tertiary weights, `TRUE` forces upper case letters to sort before lower case letters, `FALSE` does the opposite
`case_level`	single logical value; controls whether an extra case level (positioned before the third level) is generated or not
`normalization`	single logical value; if `TRUE`, then incremental check is performed to see whether the input data is in the FCD form. If the data is not in the FCD form, incremental NFD normalization is performed
`numeric`	single logical value; when turned on, this attribute generates a collation key for the numeric value of substrings of digits; this is a way to get '100' to sort AFTER '2'
`...`	any other arguments to this function are purposely ignored

ICU's collator performs a locale-aware, natural-language alike string comparison. This is a more reliable way of establishing relationships between string than that provided by base R, and definitely one that is more complex and appropriate than ordinary byte-comparison.

A note on collation strength: generally, strength set to 4 is the least permissive. Set to 2 to ignore case differences. Set to 1 to also ignore diacritical differences.

The strings are Unicode-normalized before the comparison.

Returns a named list object; missing settings are left with default values.

Collation – ICU User Guide, http://userguide.icu-project.org/collation

ICU Collation Service Architecture – ICU User Guide, http://userguide.icu-project.org/collation/architecture

icu::Collator Class Reference – ICU4C API Documentation, http://www.icu-project.org/apiref/icu4c/classicu_1_1Collator.html

Other locale_sensitive: %s<%, stri_compare, stri_count_boundaries, stri_duplicated, stri_enc_detect2, stri_extract_all_boundaries, stri_locate_all_boundaries, stri_order, stri_sort, stri_split_boundaries, stri_trans_tolower, stri_unique, stri_wrap, stringi-locale, stringi-search-boundaries, stringi-search-coll

Other search_coll: stringi-search-coll, stringi-search

stri_cmp("number100", "number2")
stri_cmp("number100", "number2", opts_collator=stri_opts_collator(numeric=TRUE))
stri_cmp("number100", "number2", numeric=TRUE) # equivalent
stri_cmp("above mentioned", "above-mentioned")
stri_cmp("above mentioned", "above-mentioned", alternate_shifted=TRUE)