how to do re.compile() with a list in python

Question

I have a list of strings in which I want to filter for strings that contains keywords.

I want to do something like:

fruit = re.compile(\'apple\', \'         


        

Answer 1

You can create one regular expression, which will match, when any of the terms is found:

>>> s, t = "A kiwi, please.", "Strawberry anyone?"
>>> import re
>>> pattern = re.compile('apple|banana|peach|plum|pineapple|kiwi', re.IGNORECASE)
>>> pattern.search(s)
<_sre.SRE_Match object at 0x10046d4a8>
>>> pattern.search(t) # won't find anything

Answer 2

Pyhton 3.x Update:

fruit_list = ['apple', 'banana', 'peach', 'plum', 'pineapple', 'kiwi']
fruit = re.compile(r'\b(?:{0})\b'.format('|'.join(fruit_list))

Answer 3

You need to turn your fruit list into the string apple|banana|peach|plum|pineapple|kiwi so that it is a valid regex, the following should do this for you:

fruit_list = ['apple', 'banana', 'peach', 'plum', 'pineapple', 'kiwi']
fruit = re.compile('|'.join(fruit_list))

edit: As ridgerunner pointed out in comments, you will probably want to add word boundaries to the regex, otherwise the regex will match on words like plump since they have a fruit as a substring.

fruit = re.compile(r'\b(?:%s)\b' % '|'.join(fruit_list))

Answer 4

As you want exact matches, no real need for regex imo...

fruits = ['apple', 'cherry']
sentences = ['green apple', 'yellow car', 'red cherry']
for s in sentences:
    if any(f in s for f in fruits):
        print s, 'contains a fruit!'
# green apple contains a fruit!
# red cherry contains a fruit!

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EDIT: If you need access to the strings that matched:

from itertools import compress

fruits = ['apple', 'banana', 'cherry']
s = 'green apple and red cherry'

list(compress(fruits, (f in s for f in fruits)))
# ['apple', 'cherry']

Answer 5

Code:

fruits =  ['apple', 'banana', 'peach', 'plum', 'pinepple', 'kiwi'] 
fruit_re = [re.compile(fruit) for fruit in fruits]
fruit_test = lambda x: any([pattern.search(x) for pattern in fruit_re])

Example usage:

fruits_veggies = ['this is an apple', 'this is a tomato']
return [fruit_test(str) for str in fruits_veggies]

Edit: I realized Andrew's solution is better. You could improve fruit_test with Andrew's regular expression as

fruit_test = lambda x: andrew_re.search(x) is None