Replace Occurrences of a Pattern

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

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)


character vector with strings to search in


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


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


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


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;


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.


All the functions return a character vector.

See Also

Other search_replace: stri_replace_na, stri_trim_both, stringi-search

  • stri_replace_all
  • stri_replace_first
  • stri_replace_last
  • stri_replace
  • stri_replace_all_charclass
  • stri_replace_first_charclass
  • stri_replace_last_charclass
  • stri_replace_all_coll
  • stri_replace_first_coll
  • stri_replace_last_coll
  • stri_replace_all_fixed
  • stri_replace_first_fixed
  • stri_replace_last_fixed
  • stri_replace_all_regex
  • stri_replace_first_regex
  • stri_replace_last_regex
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 ')

# }
# named capture groups available since ICU 55
stri_replace_all_regex("words 123 and numbers 456",
   "(?<numbers>[0-9]+)", "!${numbers}!")
# }
# 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)

# }
Documentation reproduced from package stringi, version 1.2.4, License: file LICENSE

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