Python: get list indexes using regular expression?

Question

In Python, how do you get the position of an item in a list (using list.index) using fuzzy matching?

For example, how do I get the indexes of all fruit of the form *berry in the following list?

fruit_list = ['raspberry', 'apple', 'strawberry']
# Is it possible to do something like the following?
berry_fruit_at_positions = fruit_list.index('*berry')

Anyone have any ideas?

Regular expressions aren't fuzzy, either. Just the opposite, actually: they're very strict and precise. — Glenn Maynard
– Glenn Maynard, Commented Nov 10, 2010 at 16:02

Steven Rumbalski · Accepted Answer · 2010-11-10 15:33:05Z

71

With regular expressions:

import re
fruit_list = ['raspberry', 'apple', 'strawberry']
berry_idx = [i for i, item in enumerate(fruit_list) if re.search('berry$', item)]

And without regular expressions:

fruit_list = ['raspberry', 'apple', 'strawberry']
berry_idx = [i for i, item in enumerate(fruit_list) if item.endswith('berry')]

answered Nov 10, 2010 at 15:33

Steven Rumbalski

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2 Comments

tblznbits Over a year ago

This answer should have been selected as the answer.

Sean Murphy Over a year ago

I still find it odd that this is the easiest way to do this fairly common operation in python. In R it would just be grep('berry$', berry_idx). Is there no module that implements a cleaner way to search and get integer locations?

eumiro · Accepted Answer · 2010-11-10 15:29:22Z

34

Try:

fruit_list = ['raspberry', 'apple', 'strawberry']
[ i for i, word in enumerate(fruit_list) if word.endswith('berry') ]

returns:

[0, 2]

Replace endswith with a different logic according to your matching needs.

answered Nov 10, 2010 at 15:29

eumiro

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Comments

Dorian Grv · Accepted Answer · 2018-11-29 10:53:02Z

3

with a function :

import re
fruit_list = ['raspberry', 'apple', 'strawberry']
def grep(yourlist, yourstring):
    ide = [i for i, item in enumerate(yourlist) if re.search(yourstring, item)]
    return ide

grep(fruit_list, "berry$")

answered Nov 29, 2018 at 10:53

Dorian Grv

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