This library provides generic functions for string manipulation, such as finding and extracting substrings. When indexing a string, the first character has position 1. See Section 7.2 for some examples on string manipulation in Lua.
Receives two string arguments, and returns a number. This number indicates the first position where the second argument appears in the first argument. If the second argument is not a substring of the first one, then strfind returns nil. A third optional numerical argument specifies where to start the search. Another optional numerical argument specifies where to stop it.
Receives a string and returns its length.
Returns another string, which is a substring of s, starting at i and runing until j. If j is absent or is nil, it is assumed to be equal to the length of s. Particularly, the call strsub(s,1,j) returns a prefix of s with length j, while the call strsub(s,i) returns a suffix of s, starting at i..
Receives a string and returns a copy of that string with all upper case letters changed to lower case. All other characters are left unchanged.
Receives a string and returns a copy of that string with all lower case letters changed to upper case. All other characters are left unchanged.
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