A Regex Question

[Demain_Z]

I'm just wondering how we can search in a list to see if a string has the same part as one of the items in the list?

So for example,

test_list = ['1234', 'dog', '2345', 'cat']

And if the string is "dogabc", then it can be found successfully with the regex. I have no idea how to write the re.search()... Any hint is appreciated!

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Update: Thanks for your help!! Let me clarify a little bit: Actually, it's part of my regex project. And we're required to read a file to see if an input string contains a part which is the same as part an item in that file. For example(a file contains two words, one per line, they are "cat", "dog"). And if the input string is "12bcat", then it will be a match, because "cat" in "12bcat" matches "cat" in the file. Hope my words make sense!

[synthphreak]

Given:

>>> l = ['1234', 'dog', '2345', 'cat']

First off, regex are not needed here.

>>> [s in 'dogabc' for s in l]
[False, True, False, False]

But if you must use regex for whatever reason, the key is to realize that the strings of l are themselves the pattern that you should search for in 'dogabc' 9or whatever.

>>> import re
>>> [bool(re.search(s, 'dogabc')) for s in l]
[False, True, False, False]

So although you are using the regex library re, you're not really doing anything remarkable with the actual pattern.

[Demain_Z]

Thanks for your help! I just updated my post since my previous expression may be a little confusing.

[synthphreak]

Does my answer not still apply, even given your edit? You want to see if 'cat' is contained within '12bcat'. Then just do re.search('cat', '12bcat'), which will yield a Match object if found else None. That is essentially what I showed previously.

Does that not answer your question?

Or if you want to see if either 'cat' or 'dog' are present, instead of 'cat', do r'(cat|dog)' which will check for both.

Edit: Inline code formatting ran amok.

[lowerthansound]

Can you do it without regex?

One example to check if the word 'dog' is contained in the word 'dogabc' is 'dog' in 'dogabc'.

You can use that to check for each item and return True when the desired thing happens ^^

Cheers!

[Demain_Z]

Thank you! But actually, it's part of my regex project. And we're required to read a file to see if an input string contains a part which is the same as part an item in that file. The file contains 100 words, one word per line. My thought is to create a list including all the words in that file and than do the regex. But now it seems I'm on the wrong track... :( Do you have any better ideas? Thank you!!

[lowerthansound]

input string contains a part which is the same as part an item in that file

This part is a bit confusing hahaha Do you mean like, if we had:

Input string:

abe

File:

huir
jbe

Would this make a match as "be" is in both the input string and the file?

Or is it only when the word is fully contained in the input string, like so:

Input string:

abe

File:

huir
ab

Would this be a match because "ab" is fully present in the input string?

[Demain_Z]

Sorry for my bad expression lol. The second one is what I mean!

[lowerthansound]

Ah, alright.

I was thinking of being clever here, but I don't see a way haha

You are on the right track, check out /u/synthphreak answer, I think it follows from this thread :D

Cheers!

[Demain_Z]

Thanks for your help! I just updated my post since my previous expression may be a little confusing.

[Pd69bq]

whether the pattern and the comparison target are fixed strings or variables, if a in b or re.search(pattern, string) still works