Python 3: Finding string in a list, returns the strings and NONE

Question

Code:

def find(string_list, search):
    new_list = []
    for i in string_list:
        if search in i:
            new_list.append(i)
    print(new_list)

print(find(['she', 'sells', 'sea', 'shells', 'on', 'the', 'sea-shore'], 'he'))

Returns:

['she', 'shells', 'the']
None

Default return value of a function is `None`. Remove the print call from `print(find(...` — Ashwini Chaudhary, Aug 06 '13 at 12:41
The list is printed in the function. And the None is the result of the function. — zhangyangyu, Aug 06 '13 at 12:41

score 3 · Answer 1 · answered Aug 06 '13 at 12:42

3

You're not returning anything, so the function returns None by default. Also, you can do this in a more Pythonic way:

def find(string_list, search):
    return [i for i in string_list if search in i]

This is called a list comprehension, and you can read more about them here.

answered Aug 06 '13 at 12:42

arshajii

127,459
24
238
287

At least link to an explanation on [list comprehensions](http://docs.python.org/3/tutorial/datastructures.html#list-comprehensions) - they aren't obvious for someone completely new to Python. – thegrinner Aug 06 '13 at 12:44
@thegrinner You are correct, I added that. – arshajii Aug 06 '13 at 12:45
Thank you. I appreciate the more efficient version. – user2656793 Aug 06 '13 at 12:53

score 2 · Answer 2 · answered Aug 06 '13 at 12:42

2

This is the solution

def find(string_list, search):
    new_list = []
    for i in string_list:
        if search in i:
            new_list.append(i)
    return new_list

print(find(['she', 'sells', 'sea', 'shells', 'on', 'the', 'sea-shore'], 'he'))

answered Aug 06 '13 at 12:42

Smarties89

561
3
10

Thanks so much. The simple switch does the trick! :) – user2656793 Aug 06 '13 at 12:53

Python 3: Finding string in a list, returns the strings and NONE

2 Answers2