Regular Expression for getting everything after last slash

Question

I was browsing stackoverflow and have noticed a regular expression for matching everything after last slash is

([^/]+$)

So for example if you have http://www.blah.com/blah/test The reg expression will extract 'test' without single quotes.

My question is why does it do it? Doesn't ^/ mean beginning of a slash?

EDIT: I guess I do not understand how +$ grabs "test". + repeats the previous item once or more so it ignores all data between all the / slashes. how does then $ extract the test

An awesome resource for these kinds of questions is http://regexr.com (go here: http://regexr.com?2vpj8 for your actual expression and if you hover over each part of it, you get a nice description of what that rule does). — Chris Cashwell, Jan 20 '12 at 17:43
An awesome resource for these kinds of questions is http://regexr.com ([go here](http://regexr.com?2vpj8) for your actual expression and if you hover over each part of it, you get a nice description of what that rule does). — Chris Cashwell, Jan 20 '12 at 17:49

score 50 · Answer 1 · answered Dec 22 '17 at 13:21

50

In original question, just a backslash is needed before slash, in this case regex will get everything after last slash in the string

([^\/]+$)

answered Dec 22 '17 at 13:21

Behzad

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escaping "/" is not needed when inside "[ ]" – Cezar D. Oct 02 '20 at 12:53

score 37 · Accepted Answer · answered Jan 20 '12 at 17:36

37

No, an ^ inside [] means negation.

[/] stands for 'any character in set [/]'.

[^/] stands for 'any character not in set [/]'.

answered Jan 20 '12 at 17:36

Dmitry Ovsyanko

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I guess I do not understand how +$ grabs "test". + repeats the previous item once or more so it ignores all data between all the / slashes. how does then $ extract the test. – CodeCrack Jan 20 '12 at 17:56
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@CodeCrack `[^/]` matches one non-slash; `[^/]+` matches the first non-slashes only substring; `[^/]+$` matches the non-slashes substring right at the end of what you test. – Dmitry Ovsyanko Jan 23 '12 at 16:07
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Please edit the answer to speak directly to the question instead of just having it in the comments. – Hack-R Jul 04 '17 at 03:43

score 4 · Answer 3 · answered Aug 01 '19 at 17:48

Just fyi, for a non-regex version of this, depending on the language you're in, you could use a combination of the substring and lastIndexOf methods. Just find the last index of the "/" character, and get the substring just after it.

i.e., in Java

String targetString = "a/string/with/slashes/in/it";
int lastSlashIndex = targetString.lastIndexOf('/');
String everythingAfterTheFinalSlash = targetString.substring(lastSlashIndex + 1);

score 2 · Answer 4 · answered Jan 20 '12 at 17:37

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Within brackets, ^/ means NOT A /. So this is matching a sequence of non-/'s up to the end of the line.

answered Jan 20 '12 at 17:37

Scott Hunter

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score 1 · Answer 5 · answered Jan 20 '12 at 17:35

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^ at the start of [] is character class negation. [...] specifies a set of characters to match. [^...] means match every character except that set of characters.

So [^/] means match every possible character except /.

answered Jan 20 '12 at 17:35

ʞɔıu

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score 0 · Answer 6 · answered Jan 20 '12 at 17:36

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if you put the ^ in a group it says all charters not in this group. So match all charter that are not slashes until the end of line $ anchor.

answered Jan 20 '12 at 17:36

rerun

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score 0 · Answer 7 · answered Jan 20 '12 at 17:40

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No, the ^ means different things depending on context. When inside a character class (the [] ), the ^ negates the expression, meaning "match anything except /.

Outside of [], the ^ means what you just said.

answered Jan 20 '12 at 17:40

jmatias

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Regular Expression for getting everything after last slash

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