regex - exclude substring contains more than 2 "/"

Question

I have a list of the following strings:

/fajwe/conv_1/routing/apwfe/afjwepfj
/fajwe/conv_2/routing/apwfe
/fajwe/conv_2/routing
/fajwe/conv_3/routing/apwfe/afjwepfj/awef
/fajwe/conv_4/routing/apwfe/afjwepfj/awef/0o09

I want a regex to only match string contains no more than 1 / after the word routing. Namely /fajwe/conv_2/routing/apwfe and /fajwe/conv_2/routing.

Currently I use the regex ^((?!rou\w+(\/\w+){2,}).)*$ but it matches nothing. How can I write a regex to exclude strings contains more than 2 / after the word routing?

I would love to learn how to achieve this using Negative Lookbehind. Many thanks!

Why not use a simple regex like [`^.*?/routing/?[^/]*$`](https://regex101.com/r/b26Nw8/1/tests) — bobble bubble, Apr 01 '18 at 12:35

score 1 · Answer 1 · answered Apr 01 '18 at 12:09

1

Something like this?

^.*\/routing(\/[^\/]*){0,1}$

answered Apr 01 '18 at 12:09

gandaliter

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These both match the same thing `^.*\/routing(?:\/[^\/]*)?$` – revo Apr 01 '18 at 12:13
thanks for your help! However I tested it on regex101 and it doesn't work. – spacegoing Apr 01 '18 at 12:14
1

You should enable multiline flag `m`. @spacegoing – revo Apr 01 '18 at 12:14
@revo Thanks for your comment! It works! Would you please show me how to use Negative Lookbehind to achieve this? – spacegoing Apr 01 '18 at 12:19

score 1 · Answer 2 · edited Apr 01 '18 at 12:39

1

routing(\/[^\/]*)?$

there you go

https://regex101.com/r/KjE8ed/1/

edited Apr 01 '18 at 12:39

bobble bubble

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answered Apr 01 '18 at 12:20

Schorsch

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The fourth bird · Accepted Answer · 2018-04-01T12:32:25.770

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Your regex matches what you are looking for with the multiline flag m as @revo pointed out.

^((?!rou\w+(\/\w+){2,}).)*$

You could also try it like this:

^\/fajwe\/conv_\d\/routing(?:\/[^\/]+)?$

Depending of your context of language you could \/ escape the forward slash

edited Apr 01 '18 at 12:32

answered Apr 01 '18 at 12:14

The fourth bird

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Yes it turned out that I forgot the `m` flag. Many thanks! – spacegoing Apr 01 '18 at 12:22

regex - exclude substring contains more than 2 "/"

3 Answers3