Python：如何使用（列表中项目的项目中为“str”）？

Question

The code snippet below returns an error that global name 'item' is not defined. How do I use if any(...) correctly to search for and print a string if found in a list?

def walk:
    list = ["abc", "some-dir", "another-dir", ".git", "some-other-dir"]
    if any (".git" in item for item in list):
        print item,

Answer 1

You don't. Don't use any() if you want to enumerate all the matching items. The name item only exists in the scope of the generator expression passed to any() , all you get back from the function is True or False . The items that matched are no longer available.

Just loop directly over the list and test each in an if test:

for item in lst:
    if ".git" in item:
        print item,

or use a list comprehension, passing it to str.join() (this is faster than a generator expression in this specific case ):

print ' '.join([item for item in list if ".git" in item])

or, using Python 3 syntax:

from __future__ import print_function

print(*(item for item in list if ".git" in item))

If you wanted to find just the first such a match, you can use next() :

first_match = next(item for item in list if ".git" in item)

Note that this raises StopIteration if there are no such matches, unless you give next() a default value instead:

first_match = next((item for item in list if ".git" in item), None)
if first_match is not None:
    print first_match,