string.gsub
Lua function string.gsub Summary Substitute strings inside another string Prototype `s = string.gsub (str, pattern, replacement, n)` Description `Returns a copy of str with matches to 'pattern' replaced by 'replacement', for a maximum of n times. As a second result it returns the number of matches made. 'replacement' can be a string in which case it simply replaces the matching pattern. However %1 through to %9 in the replacement pattern can refer to captured strings in the source pattern. %% becomes %. If 'replacement' is a function it is called for each match with the matching string as an argument. It should return a string which is the string to replace it with. If it returns nil the original string is retained. If 'replacement' is a table then the matching string is looked up in the table for each match, and if found, the replacement is substituted. See string.find for an explanation of regular expressions.
    string.gsub ("nick eats fish", "fish", "chips") --> nick eats chips

    -- example of using a function as the replacement

    replacements = {
       ["nice"] = "windy",
       ["walk"] = "stroll",
       }

    s = "a nice long walk"

    result = string.gsub (s, "%a+",
      function (str)
      return replacements [str]
      end
      )

    print (result) --> a windy long stroll

    -- An alternative way of doing a table replacement using the above table:

    result = string.gsub (s, "%a+", replacements)

    print (result) --> a windy long stroll

    -- You can call inbuilt functions too:

    s = "a nice long walk"

    result = string.gsub (s, "%f[%a]%a%a", string.upper)

    print (result) --> a NIce LOng WAlk
` See Also ... Topics Lua base functions Lua bc (big number) functions Lua bit manipulation functions Lua coroutine functions Lua debug functions Lua io functions Lua math functions Lua os functions Lua package functions Lua PCRE regular expression functions Lua script extensions Lua string functions Lua table functions Lua utilities Regular Expressions Scripting Lua functions string.byte (Converts a character into its ASCII (decimal) equivalent) string.char (Converts ASCII codes into their equivalent characters) string.dump (Converts a function into binary) string.find (Searches a string for a pattern) string.format (Formats a string) string.gfind (Iterate over a string (obsolete in Lua 5.1)) string.gmatch (Iterate over a string) string.len (Return the length of a string) string.lower (Converts a string to lower-case) string.match (Searches a string for a pattern) string.rep (Returns repeated copies of a string) string.reverse (Reverses the order of characters in a string) string.sub (Returns a substring of a string) string.upper (Converts a string to upper-case) (Help topic: lua=string.gsub) Documentation contents page