This is the standard way to escape the magic characters.

%*x*: (where x is any non-alphanumeric character) represents the character x.

%z: represents the character with representation 0.

%w: represents all alphanumeric characters.

%p: represents all punctuation characters.

x: (where x is not one of the magic characters ^$()%.*+-?) represents the character x itself.

The following combinations are allowed in describing a character class: X = string.gsub('hello world from Lua', '(%w+)%s*(%w+)', '%2 %1')Ī character class is used to represent a set of characters. Here are some examples: x = string.gsub('hello world', '(%w+)', '%1 %1') If the value returned by the table query or by the function call is a string or a number, then it is used as the replacement string otherwise, if it is false or nil, then there is no replacement (that is, the original match is kept in the string).

If repl is a function, then this function is called every time a match occurs, with all captured substrings passed as arguments, in order if the pattern specifies no captures, then the whole match is passed as a sole argument. If repl is a table, then the table is queried for every match, using the first capture as the key if the pattern specifies no captures, then the whole match is used as the key. The sequence %0 stands for the whole match. The character % works as an escape character: any sequence in repl of the form %*n*, with n between 1 and 9, stands for the value of the n-th captured substring (see below). If repl is a string, then its value is used for replacement. gsub also returns, as its second value, the total number of matches that occurred.

Returns a copy of s in which all (or the first n, if given) occurrences of the pattern have been replaced by a replacement string specified by repl, which can be a string, a table, or a function.

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