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[vladislavbyk]

Come on guys. Lua's patterns have always been difficult. Give vlad a break.

Besides, getting the pattern is actually tricker than it looks. BlackBulletV, who is very experienced with Lua, got it wrong (his pattern will fail with files with a double extension, such as myfile.tar.gz).

Here's what I'd use to get the file name only (this is what vlad needs - probably there's a simpler pattern, but this one works very well):

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function getBasename(filename)
  return filename:match("^([^%.]*)%.?") -- "myfile.lua" -> "myfile"
end

Here's an extended version (compatible with the previous one) which does a little more; it returns the corresponding extension:

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function getBasenameAndExtension(filename)
  return filename:match("^([^%.]*)%.?(.*)$") -- "myfile.lua" -> "myfile", "lua"
end

Tests:

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for _,filename in ipairs({"myfile.lua", "myfile", ".bashrc", "myfile.tar.gz", "myfile.yeah-baby.yeah"}) do
  print(("getBasename(%q) = %q"):format(filename, getBasename(filename)))
  print(("getBasenameAndExtension(%q) = %q, %q"):format(filename, getBasenameAndExtension(filename)))
end

Result:

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getBasename("myfile.lua") = "myfile"
getBasenameAndExtension("myfile.lua") = "myfile", "lua"
getBasename("myfile") = "myfile"
getBasenameAndExtension("myfile") = "myfile", ""
getBasename(".bashrc") = ""
getBasenameAndExtension(".bashrc") = "", "bashrc"
getBasename("myfile.tar.gz") = "myfile"
getBasenameAndExtension("myfile.tar.gz") = "myfile", "tar.gz"
getBasename("myfile.yeah-baby.yeah") = "myfile"
getBasenameAndExtension("myfile.yeah-baby.yeah") = "myfile", "yeah-baby.yeah"

Nice, thanks you very much for explanation!

[bartbes]

his pattern will fail with files with a double extension, such as myfile.tar.gz

This is unfortunate, we have wildly different views here, then. Tar.gz is perhaps the only double extension I do care about, otherwise it's generally just a dot in the filename. Also, I wouldn't say the extension of ".bashrc" is "bashrc".

[kikito]

Tar.gz is perhaps the only double extension I do care about

To be completely honest it's the same case to me - in LÖVE I doubt I'll ever need any other "composed" file extension. But if I get a .tar.gz, I want the thing to work intuitively and remove the gz and the tar too, dammit!

In ruby on rails I there is a lot more of double/triple extension: index.html.erb and script.js.coffee.erb are not uncommon.

Also, I wouldn't say the extension of ".bashrc" is "bashrc".

I don't have a strong opinion about that; It was simpler to implement that way, so I did. I doubt many of LÖVERs will have to deal with .dotfiles anyway. The test is there to ensure that the functions work without error in all cases (i.e. not raising errors or returning nils) not to express a particular personal preference.

[BlackBulletIV]

Besides, getting the pattern is actually tricker than it looks. BlackBulletV, who is very experienced with Lua, got it wrong (his pattern will fail with files with a double extension, such as myfile.tar.gz).

Ah yes, you are correct. Never thought about that since I never deal with double extensions these days.

EDIT: Just for the hell of it, here's how to extract the filename from a path with folders:

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path:match("([^/]+)$")
("foo/bar/image.png"):match("([^/]+)$") -- image.png

You could also run kikito's getBasename on the string before or after that match to remove the extension.