stringi: stri_subset – R documentation

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stri_subset

Select Elements that Match a Given Pattern

Description

These functions return or modify a sub-vector where there is a match a given pattern. In other words, they are roughly equivalent (but faster and easier to use) to a call to str[stri_detect(str, ...)] or str[stri_detect(str, ...)] <- value.

Usage

stri_subset(str, ..., regex, fixed, coll, charclass)

stri_subset(str, ..., regex, fixed, coll, charclass) <- value

stri_subset_fixed(
  str,
  pattern,
  omit_na = FALSE,
  negate = FALSE,
  ...,
  opts_fixed = NULL
)

stri_subset_fixed(str, pattern, negate=FALSE, ..., opts_fixed=NULL) <- value

stri_subset_charclass(str, pattern, omit_na = FALSE, negate = FALSE)

stri_subset_charclass(str, pattern, negate=FALSE) <- value

stri_subset_coll(
  str,
  pattern,
  omit_na = FALSE,
  negate = FALSE,
  ...,
  opts_collator = NULL
)

stri_subset_coll(str, pattern, negate=FALSE, ..., opts_collator=NULL) <- value

stri_subset_regex(
  str,
  pattern,
  omit_na = FALSE,
  negate = FALSE,
  ...,
  opts_regex = NULL
)

stri_subset_regex(str, pattern, negate=FALSE, ..., opts_regex=NULL) <- value

Arguments

`str`	character vector; strings to search in
`...`	supplementary arguments passed to the underlying functions, including additional settings for `opts_collator`, `opts_regex`, `opts_fixed`, and so on
`value`	character vector to be substituted with; replacement function only
`pattern, regex, fixed, coll, charclass`	character vector; search patterns; for more details refer to stringi-search; the replacement functions accept only one pattern at a time
`omit_na`	single logical value; should missing values be excluded from the result?
`negate`	single logical value; whether a no-match is rather of interest
`opts_collator, opts_fixed, opts_regex`	a named list used to tune up the search engine's settings; see `stri_opts_collator`, `stri_opts_fixed`, and `stri_opts_regex`, respectively; `NULL` for the defaults

Details

Vectorized over str, and pattern or value (replacement version) (with recycling of the elements in the shorter vector if necessary).

stri_subset and stri_subset<- are convenience functions. They call either stri_subset_regex, stri_subset_fixed, stri_subset_coll, or stri_subset_charclass, depending on the argument used.

Value

The stri_subset functions return a character vector. As usual, the output encoding is always UTF-8.

The stri_subset<- function modifies the str object 'in-place'.

Examples

stri_subset_regex(c('stringi R', '123', 'ID456', ''), '^[0-9]+$')

x <- c('stringi R', '123', 'ID456', '')
stri_subset_regex(x, '[^0-9]+|^$') <- NA
print(x)

x <- c('stringi R', '123', 'ID456', '')
stri_subset_regex(x, '^[0-9]+$', negate=TRUE) <- NA
print(x)

stringi

Character String Processing Facilities

v1.6.1

file LICENSE

Authors

Marek Gagolewski [aut, cre, cph] (<https://orcid.org/0000-0003-0637-6028>), Bartek Tartanus [ctb], and others (stringi source code); IBM, Unicode, Inc. and others (ICU4C source code, Unicode Character Database)

Initial release

2021-05-05