How to get number after last slash using regex?

Question

For a URL such as this:

http://www.walmart.com/ip/0982724/some-text-here/234397280?foo=bar

How can I get a variable length number after the last slash?

I tried using this regex:

\/([0-9]+)

But it gets the first number, not the last one.

Demo: http://regex101.com/r/nU3wG2

I tried adding a dollar sign at the end, but then there were no matches.

@RobertHarvey That gets all characters after the last slash, not just the number. — Nate, Mar 11 '14 at 23:28
Yes, I know. You probably should be using a Split function anyway. — Robert Harvey, Mar 11 '14 at 23:37

score 6 · Accepted Answer · answered Mar 11 '14 at 23:27

6

You can use this lookahead based regex:

\/([0-9]+)(?=[^\/]*$)

Online Demo: http://regex101.com/r/eL3mK3

This means find a number which is followed by 0 or more non-slash string till end.

answered Mar 11 '14 at 23:27

anubhava

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Why not just `\/([0-9]+)\?` or `\/([0-9]+)[^\/]*$`? – Emmet Mar 11 '14 at 23:33
You can do that but then you need to get back reference to matched group # 1 – anubhava Mar 11 '14 at 23:36
Your answer also has a capture group. – Emmet Mar 11 '14 at 23:39
the goal is last numbers, the look ahead is not needed. \d instead of [0-9] and @emment the capture is needed. – alexmac Mar 11 '14 at 23:48
Same regex can be written in more than one way isn't it? – anubhava Mar 12 '14 at 00:10

score 2 · Answer 2 · answered Mar 11 '14 at 23:34

You can do it without a rarely implemented lookahead feature if you can work with contents of capturing groups.

\/([0-9]+)[^\/]*$

Online demo: http://regex101.com/r/yG2zN1

This means "find a slash followed with any positive number of digits followed with any non-slash characters followed with end of the line". As regexps find the longest leftmost match, all of those digits are captured into a group.

score 0 · Answer 3 · answered Mar 11 '14 at 23:42

0

$aa = "http://www.walmart.com/ip/0982724/some-text-here/234397280?foo=bar";

$aa =~ /\/(\d+)\D+$/;

print $1, "\n";

This prints 234397280 \D is any non digit \d is any digit it is the same as '[0-9]

answered Mar 11 '14 at 23:42

alexmac

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Anyone remember the tv show, name that tune? I can name that song in three notes etc... I can do that regular expression in 10 characters :) – alexmac Mar 11 '14 at 23:47

How to get number after last slash using regex?

3 Answers3

Online Demo: http://regex101.com/r/eL3mK3