CODEWITHSUNDEEP
regexpython-3.x
Megan7k7
Megan7k7

Reputation: 1

Regex - Find matches with the same characters at specific positions

I have a list of 8-letter sequences like this:

    ['GQPLWLEH', 'TLYSFFPK', 'TYGEIFEK', 'APYWLINK', ...]

How can I use regular expressions to find all the sequences that have the specific letters at specific positions within the sequence? For example, the letters V, I, F, or Y at the 2nd letter in the sequence and the letters M, L, F, Y at the 3rd position in the sequence.

I'm really new to RE, thanks in advance!

Upvotes: 0

Views: 85

Answers (3)

Johannes Riecken
Johannes Riecken

Reputation: 2515

Maybe you can avoid using a regexp altogether:

[x for x in mylist if x[1] in 'VIFY' and x[2] in 'MLFY']

Upvotes: 0

Nandin Borjigin
Nandin Borjigin

Reputation: 2154

\b.[VIFY][MLFY]\w*\b

This may satisfy what you want. You can play with regex online at regex101

enter image description here

Upvotes: 0

Tim Biegeleisen
Tim Biegeleisen

Reputation: 520918

You can try using the following regex pattern:

.[VIFY][MLFY].*

This will match any first character, followed by a second and third character using the logic you want.

import re
mylist = ['GQPLWLEH', 'TLYSFFPK', 'TYGEIFEK', 'APYWLINK']
r = re.compile(".[VIFY][MLFY].*")
newlist = filter(r.match, mylist)
print str(newlist)

Demo here:

Rextester

Note: I added the word BILL to your list in the demo to get something which passes the regex match.

Upvotes: 1

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