Regex not matching values

Question

So I am creating a program which reads input Strings, and sees if they contains codes within a list. I am attempting to use a regex to get the matching string, but am having a bit of a problem with my regex. Here is my code for reference:

import re

values = ["T1245F8", "T1267F8", "T1234F8"]

checkVals = ["rfgT12B45F8asd", "b65dT12B67F8lgkt", "4fgy7tgT12B34F8", "fgtrfT12B94F8fkg"]

for i in range(len(checkVals)):
    match = False
    parsedVal = re.match('T12B[0-9]{2}F8', checkVals[i])
    for j in range(len(values)):
        if parsedVal == values[j]:
            match = True
    print(match)

The output I am expecting if 3 True and 1 False statement printed out. However instead of get 4 False statements.

EDIT: Fixed a typo in my regex, but it still isn't working.

re.match anchors the search to the start of the string and the $ is your regex is anchoring to the end... so you're only going to match strings that are identical to the pattern... use re.search and remove the $ and it should work (once you add in the B in the text your pattern will fail on...) — Jon Clements
– Jon Clements, Commented Jul 10, 2017 at 16:57
You could write this as: matches = [val for val in checkVals if re.search(r'T12B\d{2}F8', val)]... (which matches all 4 - so not sure which one you're expecting to not match...) — Jon Clements
– Jon Clements, Commented Jul 10, 2017 at 17:03

Rayhane Mama · Accepted Answer · 2017-07-10 17:09:42Z

2

It may be just a typo in your question post but i think you meant:

values = ["T12B45F8", "T12B67F8", "T12B34F8"]

then, just change this line:

parsedVal = re.match('T12B[0-9]{2}F8', checkVals[i])

to this one:

parsedVal = re.search('T12B[0-9]{2}F8', checkVals[i]).group()

this will give you the actual parts you're matching.

output:

True
True
True
False

as a conclusion, the entire code should look like this:

import re

values = ["T12B45F8", "T12B67F8", "T12B34F8"]

checkVals = ["rfgT12B45F8asd", "b65dT12B67F8lgkt", "4fgy7tgT12B34F8", "fgtrfT12B94F8fkg"]

for i in range(len(checkVals)):
    match = False
    parsedVal = re.search('T12B[0-9]{2}F8', checkVals[i]).group()
    for j in range(len(values)):
        if parsedVal == values[j]:
            match = True
    print(match)

I believe this is what you're looking for.

answered Jul 10, 2017 at 17:09

Rayhane Mama

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1 Comment

Skitzafreak Over a year ago

Thank you very much. It's working as intended now :)

Community · Accepted Answer · 2020-06-20 09:12:55Z

0

I think there is 2 problems

First:

The $ at the end of the regex is not allowing any characters after

Second:

Should be searching for T12B not T12

*It is also possible you made a type while entering your test data. For example rfgT12B45F8asd will not match your current expression because it contains T12B as a prefix to your numbers not T12

Final Regex:

T12B[0-9]{2}F8

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Jul 10, 2017 at 16:59

Tony

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2 Comments

Skitzafreak Over a year ago

Yeah sorry, that was a bad typo on my end. However I made that change to the regex and I am still only getting False values for my output.

Tony Over a year ago

@Skitzafreak I think parsedVal should be a boolean value depending on if the regex found a match. Use that to check if there was a match.

Błotosmętek · Accepted Answer · 2017-07-10 16:57:57Z

-1

Remove $ from your regexp, it matches at the end of string, while your strings don't end in F8. Also, use re.search instead of re.match.

answered Jul 10, 2017 at 16:57

Błotosmętek

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1 Comment

Skitzafreak Over a year ago

Made a quick change to my code as per your suggestion, still getting all False results. My Regex was changed to T12B[0-9]{2}F8 and i changed re.match to re.search`

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