How to check if string contains any words in list using python?

Question

I have a list "stopwords" that contains ["apple", "banana", "pear", "'", "\""].

I have another variable that contains a sentence: "sentence".

I want a simple way to be able to check to see if the string "sentence" contains any words in the list "stopwords" and if it does, then throw an error without using a for loop.

3 lines to do a check is a little verbose. If there was a one liner solution or close is better. — Rolando, Dec 17 '14 at 01:30
shorter one: `if any(x in sentence for x in stopwords): print "error"` — maxint, Dec 17 '14 at 02:08

CyanogenCX · Answer 1 · 2014-12-17T02:02:27.287

-1

stopwords=["apple", "banana", "pear"]
sentence="sentence"
for item in stopwords:
    if item not in sentence:
        continue
    else:
    print("error here")

Make sure you understand the difference between pass and continue.

I don't believe there is a way to do it without a for-loop or while loop

EDIT:

Alternatively you can do just

if item in sentence: print("error here")

to save space if you want.

As Anderson Green has pointed out, if you want the program to stop on the error, do

raise Exception("error here")

edited Dec 17 '14 at 02:02

answered Dec 17 '14 at 01:39

CyanogenCX

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Can this check for single or double quotes? – Rolando Dec 17 '14 at 01:40
It works with both single and double even if they are interchanging. For example if sentence="apple" and the apple in stopwords is 'apple' this will print "error here". And vice-versa – CyanogenCX Dec 17 '14 at 01:42
I edited my answer to make it more efficient if you would like to know. – CyanogenCX Dec 17 '14 at 01:48
Why is it `print("error here")` instead of `raise Exception("error here")`? – Anderson Green Dec 17 '14 at 01:58
@AndersonGreen I apologize for that, I wasn't sure if OP wanted to program to stop if it encountered an error. – CyanogenCX Dec 17 '14 at 02:01

mhawke · Answer 2 · 2014-12-17T01:54:53.853

Use a regular expression.

import re

stopwords = ["apple", "banana", "pear"]
pattern = re.compile('|'.join(r'\b{}\b'.format(word) for word in stopwords))

>>> sentence = 'one apple for you'
>>> pattern.search(sentence) != None
True

>>> sentence = 'one crabapple each'
>>> pattern.search(sentence) != None
False

>>> sentence = 'ten apples more'
>>> pattern.search(sentence) != None
False

There is some iteration required to set up the pattern, but not when matching the pattern. Note that this re pattern also ensures that the actual word is present by itself, not as a substring of a larger word.

How to check if string contains any words in list using python?

2 Answers2