Function RegexReplace(SearchString, Pattern, Replacement[, CaseSensitive])


The function RegexReplace finds all matches with the given regular expression and replaces them with the specified replacement. The modified string is returned.

     SearchString,    ! (input) a scalar string expression
     Pattern,         ! (input) a scalar string expression
     Replacement,     ! (input) a scalar string expression
     [CaseSensitive]  ! (optional) binary



The string in which you want to find a substring matching the regex pattern.


The regular expressions pattern to match. Multilines are not supported.


The pattern to use as replacement of each found match.

CaseSensitive (optional)

The search will be case sensitive when the value is 1. The default depends on the setting of the option Case_sensitive_string_comparison, and is 1 if this option is ‘On’ and 0 if this option is ‘Off’. The default of the option Case_sensitive_string_comparison is ‘On’.


  • The used regular expressions grammar follows the implementation of the modified ECMAScript regular expression grammar in the C++ Standard Library. It follows ECMA-262 grammar and POSIX grammar, with some modifications.

  • To include a special character in a string, it should be escaped by the backslash character \ (for more information on special characters see also Formatting Strings. In regular expressions, special characters also have to be escaped in order to be included in a pattern. For example, in order to match a backslash character the pattern should contain four backslashes (see the example below).

Return Value

The function returns a new string where all replacements are applied. If the pattern was not found in the input string the returned strings is the same as the input string.


The following example will replace all vowels with a *

str := regexreplace("The quick brown fox", "a|e|i|o|u", "*" 0);

results in str being “Q**ck br*wn f*x”.

And in the following example all vowels will be replaced by the same vowel in between brackets:

str := regexreplace("The quick brown fox", "a|e|i|o|u", "[$&]" 0);

results in str being “Q[u][i]ck br[o]wn f[o]x”.

See also

The functions RegexSearch, FindReplaceStrings.