Filter elements in a list not containing multiple substrings in Python

Question

For a list of file names file_names, I try to use code below to filter file names not containing foo or bar:

file_names = ['foo_data.xlsx', 'bar_data.xlsx', 'data.xlsx']
subs = ['foo', 'bar']

for file_name in file_names:
    for sub in subs:
        if sub not in file_name:
            print(file_name)

Output:

foo_data.xlsx
bar_data.xlsx
data.xlsx
data.xlsx

But it's not working out, it should return data.xlsx.

Meanwhile, it works for containing case:

file_names = ['foo_data.xlsx', 'bar_data.xlsx', 'data.xlsx']
subs = ['foo', 'bar']

for file_name in file_names:
    for sub in subs:
        if sub in file_name:
            print(file_name)

Out:

foo_data.xlsx
bar_data.xlsx

Does someone could help to explain what's error in my code and how to fix it? Thanks.

Reference:

Does Python have a string 'contains' substring method?

user7864386 · Accepted Answer · 2022-04-28 06:57:48Z

1

Since you don't want any sub to be in the file names; one way is to wrap the inner loop with all:

for file_name in file_names:
    if all(sub not in file_name for sub in subs):
        print(file_name)

Output:

data.xlsx

answered Apr 28, 2022 at 6:57

user7864386

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Comments

Tim Biegeleisen · Accepted Answer · 2022-04-28 06:56:45Z

1

One regex approach would be to form an alternation of the blacklist substrings, then use re.search and a list comprehension to find the matches.

file_names = ['foo_data.xlsx', 'bar_data.xlsx', 'data.xlsx']
subs = ['foo', 'bar']
regex = r'(?:' + '|'.join(subs) + r')'
matches = [f for f in file_names if not re.search(regex, f)]
print(matches)  # ['data.xlsx']

answered Apr 28, 2022 at 6:56

Tim Biegeleisen

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Comments

ah bon · Accepted Answer · 2022-04-28 08:47:52Z

0

file_names = ['foo_data.xlsx', 'bar_data.xlsx', 'data.xlsx']
subs = ['foo', 'bar']

file_names1 = []

for i in range(len(file_names)): 
    if file_names[i].startswith(subs[0])==False and file_names[i].startswith(subs[1])==False:
        file_names1.append(file_names[i])

print(file_names1)

Out:

['data.xlsx']

This should work having result in file_names1.

edited Apr 28, 2022 at 8:47

ah bon

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answered Apr 28, 2022 at 7:40

vishwamgupta

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2 Comments

ah bon Over a year ago

Please note it's not obligatory to startswith or endswith elements in subs.

vishwamgupta Over a year ago

Okay, but seems like this method had solution

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