Editing WoW:API gsub

{{luaapi}}
 string.gsub(s, pattern, replace [, n])
 gsub(s, pattern, replace [, n])
 strreplace(s, pattern, replace [, n])

This is a very powerful function and can be used in multiple ways. Used simply it can replace all instances of the pattern provided with the replacement. A pair of values is returned, the modified string and the number of substitutions made. The optional fourth argument n can be used to limit the number of substitutions made:

 > = string.gsub("Hello banana", "banana", "Lua user")
 Hello Lua user  1
 > = string.gsub("banana", "a", "A", 2)  -- limit substitutions made to 2
 bAnAna  2

If a capture is used this can be referenced in the replacement string using the notation %capture_index, e.g.,

 > = string.gsub("banana", "(an)", "%1-")    -- capture any occurances of "an" and replace
 ban-an-a        2
 > = string.gsub("banana", "a(n)", "a(%1)")  -- brackets around n's which follow a's
 ba(n)a(n)a      2
 > = string.gsub("banana", "(a)(n)", "%2%1") -- reverse any "an"s
 bnanaa  2

If the replacement is a function, not a string, the arguments passed to the function are any captures that are made. If the function returns a string, the value returned is substituted back into the string. Just like string.find() we can use regular expressions to search in strings. Patterns are covered in the [http://lua-users.org/wiki/PatternsTutorial Patterns Tutorial on Lua-Users.org], and the [[pattern matching]] HOWTO.

 > = string.gsub("Hello Lua user", "(%w+)", print)  -- print any words found
 Hello
 Lua
 user
         3
 > = string.gsub("Hello Lua user", "(%w+)", function(w) return string.len(w) end) -- replace with lengths
 5 3 4   3
 > = string.gsub("banana", "(a)", string.upper)     -- make all "a"s found uppercase
 bAnAnA  3
 > = string.gsub("banana", "(a)(n)", function(a,b) return b..a end) -- reverse any "an"s
 bnanaa  2