Example list: mylist = ['abc123', 'def456', 'ghi789']
I want to retrieve an element if there's a match for a substring, like abc
sub = 'abc'
print any(sub in mystring for mystring in mylist)
above prints True if any of the elements in the list contain the pattern.
I would like to print the element which matches the substring. So if I'm checking 'abc' I only want to print 'abc123' from list.
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())
sub.lower() in s (thank you stackoverflow.com/questions/3627784/case-insensitive-in-python)
sub.lower() in s.lower(), or it won't work when s is not lowercase.
s for s in list if sub in s ? what does it even meanAll the answers work but they always traverse the whole list. If I understand your question, you only need the first match. So you don't have to consider the rest of the list if you found your first match:
mylist = ['abc123', 'def456', 'ghi789']
sub = 'abc'
next((s for s in mylist if sub in s), None) # returns 'abc123'
If the match is at the end of the list or for very small lists, it doesn't make a difference, but consider this example:
import timeit
mylist = ['abc123'] + ['xyz123']*1000
sub = 'abc'
timeit.timeit('[s for s in mylist if sub in s]', setup='from __main__ import mylist, sub', number=100000)
# for me 7.949463844299316 with Python 2.7, 8.568840944994008 with Python 3.4
timeit.timeit('next((s for s in mylist if sub in s), None)', setup='from __main__ import mylist, sub', number=100000)
# for me 0.12696599960327148 with Python 2.7, 0.09955992100003641 with Python 3.4
Use a simple for loop:
seq = ['abc123', 'def456', 'ghi789']
sub = 'abc'
for text in seq:
if sub in text:
print(text)
yields
abc123
This prints all elements that contain sub:
for s in filter (lambda x: sub in x, list): print (s)
I'd just use a simple regex, you can do something like this
import re
old_list = ['abc123', 'def456', 'ghi789']
new_list = [x for x in old_list if re.search('abc', x)]
for item in new_list:
print item
in operator is perfect for the job as seen in other responses. Regexes are a great tool, but I think it's a bit overkill here.
list, since that's the name of a built in data type (and you won't be able to dolist(x)in the future)Trueonly once, becauseanyreturns a single boolean value. It means exactly what it says: it returns a boolean that indicates ifanyof the listed things are true.anybecause it printedTruefor every element in the list.