Regular expression to remove a file's extension

Question

I am in need of a regular expression that can remove the extension of a filename, returning only the name of the file.

Here are some examples of inputs and outputs:<

Answer 1

/^(.+)(\.[^ .]+)?$/

Above pattern is wrong - it will always include the extension too. It's because of how the javascript regex engine works. The (\.[^ .]+) token is optional so the engine will successfully match the entire string with (.+) http://cl.ly/image/3G1I3h3M2Q0M

---

Here's my tested regexp solution.

The pattern will match filenameNoExt with/without extension in the path, respecting both slash and backslash separators

var path = "c:\some.path/subfolder/file.ext"
var m = path.match(/([^:\\/]*?)(?:\.([^ :\\/.]*))?$/)
var fileName = (m === null)? "" : m[0]
var fileExt  = (m === null)? "" : m[1]

dissection of the above pattern:

([^:\\/]*?)  // match any character, except slashes and colon, 0-or-more times,
             // make the token non-greedy so that the regex engine
             // will try to match the next token (the file extension)
             // capture the file name token to subpattern \1

(?:\.        // match the '.' but don't capture it
([^ :\\/.]*) // match file extension
             // ensure that the last element of the path is matched by prohibiting slashes
             // capture the file extension token to subpattern \2
)?$          // the whole file extension is optional

http://cl.ly/image/3t3N413g3K09

http://www.gethifi.com/tools/regex

This will cover all cases that was mentioned by @RogerPate but including full paths too