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 with 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 defining 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 a search engine's settings; see stri_opts_collator, stri_opts_fixed, and stri_opts_regex, respectively; NULL for default settings;

Details

By default, all the functions are vectorized over str, pattern, replacement. Then these functions scan the input string for matches of the pattern. 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 (their numbering starts from 1). In order to treat the $ character literally, 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. Using the underlying stri_replace functions will result in code running slightly faster.

If you would like to get rid of e.g. whitespaces 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 1.1.7 Index]