I'm trying to make a simple string manipulation: getting the a file's name, without the extension. Only, string.find() seem to have an issue with dots:
s = 'crate.png'
i, j = string.find(s, '.')
print(i, j) --> 1 1
And only with dots:
s = 'crate.png'
i, j = string.find(s, 'p')
print(i, j) --> 7 7
Is that a bug, or am I doing something wrong?
string.find(), by default, does not find strings in strings, it finds patterns in strings. More complete info can be found at the link, but here is the relevant part;
The '.' represents a wildcard character, which can represent any character.
To actually find the string ., the period needs to be escaped with a percent sign, %.
EDIT: Alternately, you can pass in some extra arguments, find(pattern, init, plain) which allows you to pass in true as a last argument and search for plain strings. That would make your statement;
> i, j = string.find(s, '.', 1, true) -- plain search starting at character 1
> print(i, j)
6 6
Do either string.find(s, '%.') or string.find(s, '.', 1, true)
The other answers have already explained what's wrong. For completeness, if you're only interested in the file's base name you can use string.match. For example:
string.match("crate.png", "(%w+)%.") --> "crate"
