zerodx zerodx - 6 months ago 35
Python Question

Remove empty strings from a list of strings

I want to remove all empty strings from a list of strings in python.

My idea looks like this:

while '' in str_list:
str_list.remove('')


Is there any more pythonic way to do this?

Answer

I would use filter:

str_list = filter(None, str_list) # fastest
str_list = filter(bool, str_list) # fastest
str_list = filter(len, str_list)  # a bit of slower
str_list = filter(lambda item: item, str_list) # slower than list comprehension

Tests:

>>> timeit('filter(None, str_list)', 'str_list=["a"]*1000', number=100000)
2.4797441959381104
>>> timeit('filter(bool, str_list)', 'str_list=["a"]*1000', number=100000)
2.4788150787353516
>>> timeit('filter(len, str_list)', 'str_list=["a"]*1000', number=100000)
5.2126238346099854
>>> timeit('[x for x in str_list if x]', 'str_list=["a"]*1000', number=100000)
13.354584932327271
>>> timeit('filter(lambda item: item, str_list)', 'str_list=["a"]*1000', number=100000)
17.427681922912598