stri_duplicated: Determine Duplicated Elements
Description
stri_duplicated() determines which strings in a character vector are duplicates of other elements.
stri_duplicated_any() determines if there are any duplicated strings in a character vector.
Usage
stri_duplicated(
str,
from_last = FALSE,
fromLast = from_last,
...,
opts_collator = NULL
)
stri_duplicated_any(
str,
from_last = FALSE,
fromLast = from_last,
...,
opts_collator = NULL
)
Arguments
|
a character vector |
|
a single logical value; indicates whether search should be performed from the last to the first string |
|
[DEPRECATED] alias of |
|
additional settings for |
|
a named list with ICU Collator’s options, see |
Details
Missing values are regarded as equal.
Unlike duplicated and anyDuplicated, these functions test for canonical equivalence of strings (and not whether the strings are just bytewise equal) Such operations are locale-dependent. Hence, stri_duplicated and stri_duplicated_any are significantly slower (but much better suited for natural language processing) than their base R counterparts.
See also stri_unique for extracting unique elements.
Value
stri_duplicated() returns a logical vector of the same length as str. Each of its elements indicates whether a canonically equivalent string was already found in str.
stri_duplicated_any() returns a single non-negative integer. Value of 0 indicates that all the elements in str are unique. Otherwise, it gives the index of the first non-unique element.
References
Collation - ICU User Guide, https://unicode-org.github.io/icu/userguide/collation/
See Also
The official online manual of stringi at https://stringi.gagolewski.com/
Gagolewski M., stringi: Fast and portable character string processing in R, Journal of Statistical Software 103(2), 2022, 1-59, doi:10.18637/jss.v103.i02
Other locale_sensitive: %s<%(), about_locale, about_search_boundaries, about_search_coll, stri_compare(), stri_count_boundaries(), stri_enc_detect2(), stri_extract_all_boundaries(), stri_locate_all_boundaries(), stri_opts_collator(), stri_order(), stri_rank(), stri_sort_key(), stri_sort(), stri_split_boundaries(), stri_trans_tolower(), stri_unique(), stri_wrap()
Examples
# In the following examples, we have 3 duplicated values,
# 'a' - 2 times, NA - 1 time
stri_duplicated(c('a', 'b', 'a', NA, 'a', NA))
## [1] FALSE FALSE TRUE FALSE TRUE TRUE
stri_duplicated(c('a', 'b', 'a', NA, 'a', NA), from_last=TRUE)
## [1] TRUE FALSE TRUE TRUE FALSE FALSE
stri_duplicated_any(c('a', 'b', 'a', NA, 'a', NA))
## [1] 3
# compare the results:
stri_duplicated(c('\u0105', stri_trans_nfkd('\u0105')))
## [1] FALSE TRUE
duplicated(c('\u0105', stri_trans_nfkd('\u0105')))
## [1] FALSE FALSE
stri_duplicated(c('gro\u00df', 'GROSS', 'Gro\u00df', 'Gross'), strength=1)
## [1] FALSE TRUE TRUE TRUE
duplicated(c('gro\u00df', 'GROSS', 'Gro\u00df', 'Gross'))
## [1] FALSE FALSE FALSE FALSE