Python - check if string contains any element from a list

Question

I need to check whether a string contains any element of a list. I'm currently using this method:

engWords = ["the", "a", "and", "of", "be", "that", "have", "it", "for", "not"]
engSentence = "the dogs fur is black and white"

print("the english sentence is: " + engSentence)

engWords2 = []
isEnglish = 0

for w in engWords:
    if w in engSentence:
        isEnglish = 1
        engWords2.append(w)

if isEnglish == 1:
    print("The sentence is english and contains the words: ")
    print(engWords2)

The problem with this is that it gives the output:

the english sentence is: the dogs fur is black and white
The sentence is english and contains the words: 
['the', 'a', 'and', 'it']
>>>

As you can see 'a' and 'it' should not be present. How can i search so that it will only list individual words, rather than parts of a word also? I'm open to any ideas using normal python code, or regex(although I'm very new to both python and regex, so please nothing too complicated) Thank you.

There aren't any regular expressions involved here--this is just string manipulation. regexes are a very specific way of providing match patterns against a string, and you'd be working with the re module if you were using them. — geoelectric
– geoelectric, Commented Apr 3, 2015 at 20:38
btw, worth noting that all of these solutions (mine included) only work if there's no punctuation. Any punctuation will look like part of the word it's up next to and make your comparisons fail. If you start including punctuation, you'll need some strategy to either remove or ignore it. One strategy would be to use regular expressions against the full sentence string, with a '\b' on either side of each word you search. — geoelectric
– geoelectric, Commented Apr 3, 2015 at 20:51

geoelectric · Accepted Answer · 2015-04-03 20:36:23Z

5

It's finding those two words because they're substrings of "black" and "white" respectively. When you apply "in" to a string, it just looks for substrings of characters.

try:

engSentenceWords = engSentence.split()

And later,

if w in engSentenceWords:

That splits the original sentence into a list of individual words, and then checks against whole word values.

answered Apr 3, 2015 at 20:36

geoelectric

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hexerei software · Accepted Answer · 2015-04-03 20:44:29Z

0

or even simpler, add a space to your sentence and your search word:

engWords = ["the", "a", "and", "of", "be", "that", "have", "it", "for", "not"]
engSentence = "the dogs fur is black and white"

print("the english sentence is: " + engSentence)

engWords2 = []
isEnglish = 0
engSentence += " "

for w in engWords:
    if "%s " % w in engSentence:
        isEnglish = 1
        engWords2.append(w)

if isEnglish == 1:
    print("The sentence is english and contains the words: ")
    print(engWords2)

output is:

the english sentence is: the dogs fur is black and white
The sentence is english and contains the words: 
['the', 'and']

answered Apr 3, 2015 at 20:44

hexerei software

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devinformatics · Accepted Answer · 2015-04-03 20:45:42Z

0

words = set(engSentence.split()).intersection(set(engWords))
if words:
    print("The sentence is english and contains the words: ")
    print(words)

Split the engSentence into tokens in a list, convert that to a set, convert engWords to a set, and find the intersection (common overlap). Then check to see if this is non-empty, and if so print out the words found.

edited Apr 3, 2015 at 20:45

answered Apr 3, 2015 at 20:38

devinformatics

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themeasure43 · Accepted Answer · 2017-07-06 11:02:56Z

0

You may want to use regex matching. Try something like following

import re

match_list = ['foo', 'bar', 'eggs', 'lamp', 'owls']
match_str = 'owls are not what they seem'
match_regex = re.compile('^.*({1}).*$'.format('|'.join(match_list)))

if match_regex.match(match_str):
    print('We have a match.')

See the re documentation on python.org for details.

edited Jul 6, 2017 at 11:02

answered Jul 6, 2017 at 9:56

themeasure43

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