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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,
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.
Returns the ascii code of the character s[i].
If i is absent, it is assumed to be 1.
Receives 0 or more numbers.
Returns a string with length equal to the number of arguments,
wherein each character has ascii value equal
to its correspondent argument.
Next: 6.3 Mathematical Functions
Up: 6 Predefined Functions and
Previous: 6.1 Predefined Functions