Problem to research a special character in Python

Question

I have a file (I only show a part) where I would like to remove a special character.

OTU1359 UniRef90_A0A095VQ09 UniRef90_A0A0C1UI80 UniRef90_A0A1M4ZSK2 UniRef90_A0A1W1CJV7 UniRef90_A0A1Z9J2X0 UniRef90_A0A1Z9THL2 UniRef90_A0A2E3B6A5 UniRef90_A0A2E5MT47 UniRef90_A0A2E5VCW9 UniRef90_A0A2E6CDK4 UniRef90_A0A2E6KTE6 UniRef90_A0A2E8AIM6 UniRef90_A0A2E8RIG1 UniRef90_A0A2E8YNS3 UniRef90_A0A2E9VEK0 UniRef90_W6RCT6

OTU0980 UniRef90_A0A084TMQ7 UniRef90_A0A090PK65 UniRef90_A0A0P1G8P0 UniRef90_A0A0P1IHL1 UniRef90_A0A286ILS7 UniRef90_A0A2A5E7H9 UniRef90_A0A2D9J217 UniRef90_H3NS47 UniRef90_H3NSN9 UniRef90_H3NSP0 UniRef90_H3NSP7 UniRef90_H3NUB2 UniRef90_H3NY28 UniRef90_H3NY47 UniRef90_UPI000C2CBC51

I would like to remove the character "OTUXXXX" (it always start by OTU and has always 4 numbers after) . It can appears multiple OTUXXXX by line

I tried :

re.search("OTU[0-9]{4}", line)

It doesn't work.. Any help?

Answer 1

You could make use of re.sub which actually performs replacemnt or substitution of matching text with the one you provide. Here you find the doc: https://docs.python.org/3/library/re.html

And here one possible implementaiton:

from re import compile, sub, MULTILINE

text = '''
OTU1359 UniRef90_A0A095VQ09 UniRef90_A0A0C1UI80 UniRef90_A0A1M4ZSK2 UniRef90_A0A1W1CJV7 UniRef90_A0A1Z9J2X0 UniRef90_A0A1Z9THL2 UniRef90_A0A2E3B6A5 UniRef90_A0A2E5MT47 UniRef90_A0A2E5VCW9 UniRef90_A0A2E6CDK4 UniRef90_A0A2E6KTE6 UniRef90_A0A2E8AIM6 UniRef90_A0A2E8RIG1 UniRef90_A0A2E8YNS3 UniRef90_A0A2E9VEK0 UniRef90_W6RCT6

OTU0980 UniRef90_A0A084TMQ7 UniRef90_A0A090PK65 UniRef90_A0A0P1G8P0 UniRef90_A0A0P1IHL1 UniRef90_A0A286ILS7 UniRef90_A0A2A5E7H9 UniRef90_A0A2D9J217 UniRef90_H3NS47 UniRef90_H3NSN9 UniRef90_H3NSP0 UniRef90_H3NSP7 UniRef90_H3NUB2 UniRef90_H3NY28 UniRef90_H3NY47 UniRef90_UPI000C2CBC51
'''

replacemnt = ''
regex = compile(r'OTU\d{4}', flags=MULTILINE)
cleaned = sub(regex, replacemnt, text)

Answer 2

I suggest using re.sub and find your pattern matches as whole words to avoid partial matches inside other words.

s = re.sub(r"\s*\bOTU[0-9]{4}\b", "", line).strip()

See the regex demo . The .strip() at the end removes any redundant leading/trailing whitespaces that remain after removing the matches at the end/start of the string.

See the regex graph :