Generate a List with Collator Settings

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.

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

single string, NULL or "" for default locale


single integer in {1,2,3,4}, which defines collation strength; 1 for the most permissive collation rules, 4 for the most strict ones


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


single logical value; used in Canadian French; TRUE results in secondary weights being considered backwards


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


single logical value; controls whether an extra case level (positioned before the third level) is generated or not


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


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,

ICU Collation Service Architecture -- ICU User Guide,

icu::Collator Class Reference -- ICU4C API Documentation,

See Also

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_opts_collator
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)
# }
Documentation reproduced from package stringi, version 1.4.3, License: file LICENSE

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