Need a little regex help in python

Question

I have a long list of namespaces coming from a graphite instance and am trying to run some validation and filter out the namespaces that have not been entered using the correct format.

I can do ok with regex usually, but this one is hurting me and was hoping someone could help.

There is some basic validation that needs to be done and I've come this far:

^(stats\.gauges\..*\.(?:dur|hop|scz|led|bgi|shi|crk|sas)\.(?:p|s|q|u|d|x)\.)

The goal is to filter and match on the ones following the standardized stats.gaugues.*.(exact OR match).(exact OR match).

This works ok for something like:

stats.gauges.gitswarm.dur.p.durgitswarm1.service.repos.eeps-merge_demo.users

But unfortunately someone entered some like:

stats.gauges.gitswarm.dur.p.durgitswarm1.dur.p.service.repos.eeps-merge_demo.users

So these match all the way to the second dur.p. skipping possible error on exact matches such as stats.gauges.gitswarm.durham.p.durgitswarm1.dur.p.service.repos.eeps-merge_demo.users; which I don't want.

I feel like this is something pretty simple, but can't seem to grasp it so far.

Any help would be very much appreciated.

Thank you!

So why is stats.gauges.gitswarm.durham.p.durgitswarm1.dur.p.service.repos.eeps-merge_demo.users not following the standardized stats.gaugues.*.(exact OR match).(exact OR match).? In this case * matches gitswarm.durham.p.durgitswarm1. The problem is with your definition of *. — Phu Ngo
– Phu Ngo, Commented Nov 3, 2016 at 2:23
It needs to fail because 1) dur is the valid value, not durham and 2) dur.p. should should not be in the location it is even with the invalid value. I agree it is with the definition of *, I think that is what I'm having trouble placing into regex form. — NoctemX
– NoctemX, Commented Nov 3, 2016 at 2:27

saurabh baid · Accepted Answer · 2016-11-03 02:13:58Z

2

This should work. Basically you need to make your .* non greedy ^(stats\.gauges\..*?\.(?:dur|hop|scz|led|bgi|shi|crk|sas)\.(?:p|s|q|u|d|x)\.)

answered Nov 3, 2016 at 2:13

saurabh baid

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5 Comments

Phu Ngo Over a year ago

I don't think greedy or not matters here: OP is trying to spot negative cases

NoctemX Over a year ago

I tried that too :( ^(stats\.gauges\..*?\.(?:dur|hop|scz|led|bgi|shi|crk|sas)\.(?:p|s|q|u|d|x)\.) !Regular expression visualization Debuggex Demo

saurabh baid Over a year ago

In that case can you elobrate you pattern because .* says match anything so you'll have to come up with something specific than .* Could you tell me what exactly could come in between stats.gauges. and dur.p. Would it always be one word?

NoctemX Over a year ago

Yes, exactly, it should only be one word. Just stats.gauges.{word}.dur|hop|etc.p|d|u. Sorry I didn't make that clearer early on.

NoctemX Over a year ago

I think you just helped the light bulb go off... I believe it should just be:^(stats\.gauges\.\w*\.(?:dur|hop|scz|led|bgi|shi|crk|sas)\.(?:p|s|q|u|d|x)\.)

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