Regex to get string in URL before optional character

Question

I have a URL which may be formatted like this: http://domain.com/space/all/all/FarmAnimals

or like this: http://domain.com/space/all/all/FarmAnimals?param=2

What regular expression can I use to return the expression FarmAnimals in both instances?

I am trying this:

var myRegexp = /\.com\/space\/[a-zA-Z0-9]*\/[a-zA-Z0-9]*\/(.*)/;
var match = myRegexp.exec(topURL);
var full = match[1];

but this only works in the first instance, can someone please provide an example of how to set up this regex with an optional question mark closure?

Thank you very much!

Wrikken · Accepted Answer · 2013-04-23 22:44:48Z

5

 /[^/?]+(?=\?|$)/

Any non-/ followed by either ? or and end-of-line.

edited Apr 23, 2013 at 22:44

answered Apr 23, 2013 at 22:23

Wrikken

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6 Comments

Adidi Over a year ago

returns FarmAnimals?param=2 on http://domain.com/space/all/all/FarmAnimals?param=2

femtoRgon Over a year ago

I think [^/]+ needs to be reluctant. That is: [^/]+?

femtoRgon Over a year ago

Hah, that works too! Move the question mark to a different spot, where it means something entirely different, and still fixes the problem.

Adidi Over a year ago

@Wrikken why seems wrong ? working great ! - what is the ?= sign means ? look ahead ?

Wrikken Over a year ago

Well, what I dislike about it is that "param=2" also matches (run with /g), but it would always be the second match, so no biggie. And yup, lookahead it is. I'm not used to regexes without look-behinds (which javascript doesn't support), maybe that's my unease, cause I would have thrown in a (?<=/) for good measure...

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keyboardP · Accepted Answer · 2013-04-23 22:40:44Z

2

I wouldn't write my own regex here and let the Path class handle it (if those are your two string formats).

string url = "http://domain.com/space/all/all/FarmAnimals";

//ensure the last character is not a '/' otherwise `GetFileName` will be empty
if (url.Last() == '/') url = url.Remove(url.Length - 1);

//get the filename (anything from FarmAnimals onwards)
string parsed = Path.GetFileName(url);

//if there's a '?' then only get the string up to the '?' character
if (parsed.IndexOf('?') != -1) 
    parsed = parsed.Split('?')[0];

edited Apr 23, 2013 at 22:40

answered Apr 23, 2013 at 22:34

keyboardP

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Comments

tckmn · Accepted Answer · 2013-04-23 22:22:55Z

1

You could use something like this:

var splitBySlash = topURL.split('/')
var splitByQ = splitBySlash[splitBySlash.length - 1].split('?')
alert(splitByQ[0])

Explanation:

splitBySlash will be ['http:','','domain.com', ... ,'all','FarmAnimals?param=2'].

Then splitByQ will grab the last item in that array and split it by ?, which becomes ['FarmAnimas','param=2'].

Then just grab the first element in that.

answered Apr 23, 2013 at 22:22

tckmn

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Comments

femtoRgon · Accepted Answer · 2013-04-23 22:36:54Z

1

This

.*\/(.*?)(\?.*)?$

Should capture the part of the string you are looking for as the group 1 (and the query after ? in group 2, if needed).

answered Apr 23, 2013 at 22:36

femtoRgon

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Comments

Adidi · Accepted Answer · 2013-04-23 22:31:54Z

0

var url = 'http://domain.com/space/all/all/FarmAnimals?param=2';
//var url = 'http://domain.com/space/all/all/FarmAnimals';
var index_a = url.lastIndexOf('/');
var index_b = url.lastIndexOf('?');
console.log(url.substring(index_a + 1, (index_b != -1 ? index_b : url.length)));

answered Apr 23, 2013 at 22:31

Adidi

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