Regular Expression to collect everything after the last /

Question

I'm new at regular expressions and wonder how to phrase one that collects everything after the last /.

I'm extracting an ID used by Google's GData.

my example string is

http://spreadsheets.google.com/feeds/spreadsheets/p1f3JYcCu_cb0i0JYuCu123 

Where the ID is: p1f3JYcCu_cb0i0JYuCu123

Oh and I'm using PHP.

Answer 1

This matches at least one of (anything not a slash) followed by end of the string:

[^/]+$ 

Notes:

• No parens because it doesn't need any groups - result goes into group 0 (the match itself).
• Uses + (instead of *) so that if the last character is a slash it fails to match (rather than matching empty string).

But, most likely a faster and simpler solution is to use your language's built-in string list processing functionality - i.e. ListLast( Text , '/' ) or equivalent function.

For PHP, the closest function is strrchr which works like this:

strrchr( Text , '/' ) 

This includes the slash in the results - as per Teddy's comment below, you can remove the slash with substr:

substr( strrchr( Text, '/' ), 1 ); 

Answer 2

Generally:

/([^/]*)$ 

The data you want would then be the match of the first group.

---

Edit   Since you’re using PHP, you could also use strrchr that’s returning everything from the last occurence of a character in a string up to the end. Or you could use a combination of strrpos and substr, first find the position of the last occurence and then get the substring from that position up to the end. Or explode and array_pop, split the string at the / and get just the last part.