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Author Topic: Regex Help  (Read 2017 times)

hoyt

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Regex Help
« on: December 02, 2015, 04:30:57 pm »

I'm having a hard time getting something to work in MC that I know works in an online perl regex tester.  I'm trying to parse the Description field for NFL games given the data coming into MC.  I want to then populate Home Team and Visiting Team.  Here's an example of the text:

Code: [Select]
San Francisco (3-6) at Seattle (4-5). Michael Bennett's 3.5 sacks led the Seahawks to a 20-3 rout of the Niners on Oct. 22, as Seattle allowed a season-low 142 yards. 'Hawks RB Marshawn Lynch is averaging 101.9 ypg with 10 TDs in the last nine meetings.
I then setup this:

Code: [Select]
regex([Description],/(?<=at)(.*)(?=[\(])/,-1,0)[R2]
I expect to get back ' Seattle '.  I would then trim the result.  However, I'm just getting a partial output of my regex into an expression column where I'm testing.  It shows:

Code: [Select]
0(.*)(?=[\(]),-1,0)
What am I missing?  Thanks!
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blgentry

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Re: Regex Help
« Reply #1 on: December 02, 2015, 04:36:04 pm »

Without actually analyzing the regex itself, I see one thing wrong:

MC Regex patterns start with /# and end with #/ .  So I don't think your pattern is being recognized.

Brian.
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hoyt

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Re: Regex Help
« Reply #2 on: December 02, 2015, 04:41:22 pm »

Interesting, didn't realize that.  My Regex for the Home Team is this:

Code: [Select]
RemoveCharacters(Regex([Description],(/^[^\(]+/),1), ,2)
And that works.  I added the # after and before the /'s and now the return is just blank.  That makes me feel like it's at least trying to eval the expression now though...
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hoyt

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Re: Regex Help
« Reply #3 on: December 02, 2015, 04:57:36 pm »

Without actually analyzing the regex itself, I see one thing wrong:

MC Regex patterns start with /# and end with #/ .  So I don't think your pattern is being recognized.

Brian.

Ok, that lead me in the right direction, now I have:

Code: [Select]
regex([Description],/#(?<=at)(.*)(?=[\(])#/,-1,0)[R1]
For some reason I was thinking each () would be an R#.  But now something with two ('s is matching too large of a set:

Code: [Select]
Oakland (4-5) at Detroit (2-7). Joique Bell and the Lions' 32nd-ranked ground game meet an Oakland run defense that's allowed 458 yards the last two weeks. Ex-Michigan DB Charles Woodson (5 INTs) looks to add to Detroit's league-high 21 turnovers.
Turns into:

Code: [Select]
Detroit (2-7). Joique Bell and the Lions' 32nd-ranked ground game meet an Oakland run defense that's allowed 458 yards the last two weeks. Ex-Michigan DB Charles Woodson
I need to figure out how to change that set to match until the first (, not the last, but wanted to at least update that I was getting it working with the #s.
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hoyt

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Re: Regex Help
« Reply #4 on: December 02, 2015, 05:03:27 pm »

Every time I have to do Regex, my head spins.  Here's what I ended up with that appears to work how I want:

Code: [Select]
regex([Description],/#(?<=at)(.+?)(?=[\(])#/,-1,0)[R1]
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blgentry

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Re: Regex Help
« Reply #5 on: December 02, 2015, 05:44:03 pm »

I'm pretty decent with regex, but I don't know or use it's full syntax.  For example, the (<=stuff) idiom is new to me.  I've never used it and I don't know exactly how it works.

It sounds like you've got it under control.  If you need more advice, let me know and I'll try to help.

Edit:  I couldn't help myself and had to try it myself.  Here's my take:

Code: [Select]
regex([Description],/#.+ at ([^\s]+)#/,-1,0)[R1]
The "trick" here is the stuff I'm matching on inside the () isn't just a dot character (which can be anything).  Instead I'm matching on [^\s].  Which means "match any character except space type characters".  So it stops the match when it hits the first space, tab, or other whitespace type character.

Seems a little more readable and simple to me... but then again, I wrote it, so it should seem easier to understand for ME.  :)

Brian.
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hoyt

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Re: Regex Help
« Reply #6 on: December 02, 2015, 06:02:57 pm »

I'm pretty decent with regex, but I don't know or use it's full syntax.  For example, the (<=stuff) idiom is new to me.  I've never used it and I don't know exactly how it works.

It sounds like you've got it under control.  If you need more advice, let me know and I'll try to help.

Edit:  I couldn't help myself and had to try it myself.  Here's my take:

Code: [Select]
regex([Description],/#.+ at ([^\s]+)#/,-1,0)[R1]
The "trick" here is the stuff I'm matching on inside the () isn't just a dot character (which can be anything).  Instead I'm matching on [^\s].  Which means "match any character except space type characters".  So it stops the match when it hits the first space, tab, or other whitespace type character.

Seems a little more readable and simple to me... but then again, I wrote it, so it should seem easier to understand for ME.  :)

Brian.


The <= just means up to, at least, that's how I understood it... This site makes it easy to understand by highlighting and adding notes to the side: https://regex101.com/#pcre

I think I actually need the (.*) because I want to match San Francisco, not just San.  Like you said, I got it to work and with regex there are all sorts of ways to do the same thing.  I'll keep with what I have until I come across a broadcast that breaks it :)

Thanks!
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