Finding a Substring Within a List in Python

Finding a substring within a list in Python

print [s for s in list if sub in s]

If you want them separated by newlines:

print "\n".join(s for s in list if sub in s)

Full example, with case insensitivity:

mylist = ['abc123', 'def456', 'ghi789', 'ABC987', 'aBc654']
sub = 'abc'

print "\n".join(s for s in mylist if sub.lower() in s.lower())

How to check if a string is a substring of items in a list of strings

To check for the presence of 'abc' in any string in the list:

xs = ['abc-123', 'def-456', 'ghi-789', 'abc-456']

if any("abc" in s for s in xs):
    ...

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To get all the items containing 'abc':

matching = [s for s in xs if "abc" in s]

Finding a substring in a list of lists

You need to check if StreamCache is part of any string in the list, which you could do with something like this:

[l for l in data if any('StreamCache' in s for s in l)]

If StreamCache always occurs at the beginning of the string, this would be more efficient:

[l for l in data if any(s.startswith('StreamCache') for s in l)]

Find the list indices of all occurrences of a substring within the list

Try this:

indices = [idx for idx, s in enumerate(alphabet) if name in s]

where alphabet is your list of strings, and name is the desired substring.

Python: How to check a string for substrings from a list?

Try this test:

any(substring in string for substring in substring_list)

It will return True if any of the substrings in substring_list is contained in string.

Note that there is a Python analogue of Marc Gravell's answer in the linked question:

from itertools import imap
any(imap(string.__contains__, substring_list)) 

In Python 3, you can use map directly instead:

any(map(string.__contains__, substring_list))

Probably the above version using a generator expression is more clear though.

How to check for the presence of a substring in a list of strings

You have a numpy array, not a list.

Anyway, considering a list (this would also work on a numpy array):

my_lst = ['hello', 'this', 'is', 'a', 'testello']

query = 'ello'
out = [query in e for e in my_lst]

# [True, False, False, False, True]

for a numpy array:

my_array = np.array(['hello', 'this', 'is', 'a', 'testello'])

out = np.core.defchararray.find(my_array, query)>0
# array([ True, False, False, False,  True])

Python list of substrings in list of strings

any(y in x for x in string_list for y in substrings)

How to find all occurrences of a substring?

There is no simple built-in string function that does what you're looking for, but you could use the more powerful regular expressions:

import re
[m.start() for m in re.finditer('test', 'test test test test')]
#[0, 5, 10, 15]

If you want to find overlapping matches, lookahead will do that:

[m.start() for m in re.finditer('(?=tt)', 'ttt')]
#[0, 1]

If you want a reverse find-all without overlaps, you can combine positive and negative lookahead into an expression like this:

search = 'tt'
[m.start() for m in re.finditer('(?=%s)(?!.{1,%d}%s)' % (search, len(search)-1, search), 'ttt')]
#[1]

re.finditer returns a generator, so you could change the [] in the above to () to get a generator instead of a list which will be more efficient if you're only iterating through the results once.

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