The RegSubs(env,text) command replaces each occurrence of a substring matching the left-hand side of env with the right-hand side of env in the string text.

If no substring of text matches the left-hand side of env, then text is returned unchanged.

This procedure is closely related to StringTools[RegSub], but provides a more intuitive interface. The chief difference between the two is that RegSubs effects all relevant substitutions (serially), while StringTools[RegSub] performs a single substitution. Also, the left-hand side of env cannot match an empty substring of text. (An exception is raised in this case.)

All of the StringTools package commands treat strings as (null-terminated) sequences of $8$-bit (ASCII) characters.  Thus, there is no support for multibyte character encodings, such as unicode encodings.

$\mathrm{with}\left(\mathrm{StringTools}\right)\:$

$\mathrm{RegSubs}\left(''((a))''=''gu\backslash \backslash 1v\backslash \backslash 2''\,''abc''\right)$

$''guavabc''$

$''abbbcd-abbbc''$

$''abcd-bc-d''$

$''effgz-effgz-''$

$''reffgz-effgz-''$

$\mathrm{RegSubs}\left(''(.*)c(anad[ai])(.*)''=''\backslash \backslash 1C\backslash \backslash 2\backslash \backslash 3''\,''Maple\; is\; canadian''\right)$

$''Maple\; is\; Canadian''$

$\mathrm{RegSubs}\left(''[\; \backslash t]+''=''''\,''Some\; text\; \backslash t\backslash t\; with\; extra\; \backslash t\; space.''\right)$

$''Some\; text\; with\; extra\; space.''$