stringi

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stri_replace_all {stringi}R Documentation

Replace Occurrences of a Pattern

Description

These functions replace, with the given replacement string, every/first/last substring of the input that matches the specified pattern.

Usage

stri_replace_all(str, replacement, ..., regex, fixed, coll, charclass)

stri_replace_first(str, replacement, ..., regex, fixed, coll, charclass)

stri_replace_last(str, replacement, ..., regex, fixed, coll, charclass)

stri_replace(str, replacement, ..., regex, fixed, coll, charclass,
  mode = c("first", "all", "last"))

stri_replace_all_charclass(str, pattern, replacement, merge = FALSE,
  vectorize_all = TRUE)

stri_replace_first_charclass(str, pattern, replacement)

stri_replace_last_charclass(str, pattern, replacement)

stri_replace_all_coll(str, pattern, replacement, vectorize_all = TRUE,
  ..., opts_collator = NULL)

stri_replace_first_coll(str, pattern, replacement, ...,
  opts_collator = NULL)

stri_replace_last_coll(str, pattern, replacement, ...,
  opts_collator = NULL)

stri_replace_all_fixed(str, pattern, replacement, vectorize_all = TRUE,
  ..., opts_fixed = NULL)

stri_replace_first_fixed(str, pattern, replacement, ...,
  opts_fixed = NULL)

stri_replace_last_fixed(str, pattern, replacement, ...,
  opts_fixed = NULL)

stri_replace_all_regex(str, pattern, replacement, vectorize_all = TRUE,
  ..., opts_regex = NULL)

stri_replace_first_regex(str, pattern, replacement, ...,
  opts_regex = NULL)

stri_replace_last_regex(str, pattern, replacement, ...,
  opts_regex = NULL)

Arguments

str

character vector; strings to search in

replacement

character vector with replacements for matched patterns

...

supplementary arguments passed to the underlying functions, including additional settings for opts_collator, opts_regex, opts_fixed, and so on

mode

single string; one of: "first" (the default), "all", "last"

pattern, regex, fixed, coll, charclass

character vector; search patterns; for more details refer to stringi-search

merge

single logical value; should consecutive matches be merged into one string; stri_replace_all_charclass only

vectorize_all

single logical value; should each occurrence of a pattern in every string be replaced by a corresponding replacement string?; stri_replace_all_* only

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

By default, all the functions are vectorized over str, pattern, replacement. Input that is not part of any match is left unchanged; each match is replaced in the result by the replacement string.

However, for stri_replace_all*, if vectorize_all is FALSE, the each substring matching any of the supplied patterns is replaced by a corresponding replacement string. In such a case, the vectorization is over str, and - independently - over pattern and replacement. In other words, this is equivalent to something like for (i in 1:npatterns) str <- stri_replace_all(str, pattern[i], replacement[i]. Note that you must set length(pattern) >= length(replacement).

In case of stri_replace_*_regex, the replacement string may contain references to capture groups (in round parentheses). References are of the form $n, where n is the number of the capture group ($1 denotes the first group). For the literal $, escape it with a backslash. Moreover, ${name} are used for named capture groups.

stri_replace, stri_replace_all, stri_replace_first, and stri_replace_last are convenience functions; they just call stri_replace_*_* variants, depending on the arguments used.

If you wish to remove white-spaces from the start or end of a string, see stri_trim.

Value

All the functions return a character vector.

See Also

Other search_replace: stri_replace_na, stri_trim_both, stringi-search

Examples

stri_replace_all_charclass("aaaa", "[a]", "b", merge=c(TRUE, FALSE))

stri_replace_all_charclass("a\nb\tc   d", "\\p{WHITE_SPACE}", " ")
stri_replace_all_charclass("a\nb\tc   d", "\\p{WHITE_SPACE}", " ", merge=TRUE)

s <- "Lorem ipsum dolor sit amet, consectetur adipisicing elit."
stri_replace_all_fixed(s, " ", "#")
stri_replace_all_fixed(s, "o", "0")

stri_replace_all_fixed(c("1", "NULL", "3"), "NULL", NA)

stri_replace_all_regex(s, " .*? ", "#")
stri_replace_all_regex(s, "(el|s)it", "1234")
stri_replace_all_regex('abaca', 'a', c('!', '*'))
stri_replace_all_regex('123|456|789', '(\\p{N}).(\\p{N})', '$2-$1')
stri_replace_all_regex(c("stringi R", "REXAMINE", "123"), '( R|R.)', ' r ')

## Not run: 
# named capture groups available since ICU 55
stri_replace_all_regex("words 123 and numbers 456",
   "(?<numbers>[0-9]+)", "!${numbers}!")

## End(Not run)

# Compare the results:
stri_replace_all_fixed("The quick brown fox jumped over the lazy dog.",
     c("quick", "brown", "fox"), c("slow",  "black", "bear"), vectorize_all=TRUE)
stri_replace_all_fixed("The quick brown fox jumped over the lazy dog.",
     c("quick", "brown", "fox"), c("slow",  "black", "bear"), vectorize_all=FALSE)

# Compare the results:
stri_replace_all_fixed("The quicker brown fox jumped over the lazy dog.",
     c("quick", "brown", "fox"), c("slow",  "black", "bear"), vectorize_all=FALSE)
stri_replace_all_regex("The quicker brown fox jumped over the lazy dog.",
     "\\b"%s+%c("quick", "brown", "fox")%s+%"\\b", c("slow",  "black", "bear"), vectorize_all=FALSE)


[Package stringi version 1.3.1 Index]