How do I check if a list is empty? How do I check if a list is empty? python python

How do I check if a list is empty?


if not a:  print("List is empty")

Using the implicit booleanness of the empty list is quite pythonic.


The pythonic way to do it is from the PEP 8 style guide (where Yes means “recommended” and No means “not recommended”):

For sequences, (strings, lists, tuples), use the fact that empty sequences are false.

Yes: if not seq:     if seq:No:  if len(seq):     if not len(seq):


I prefer it explicitly:

if len(li) == 0:    print('the list is empty')

This way it's 100% clear that li is a sequence (list) and we want to test its size. My problem with if not li: ... is that it gives the false impression that li is a boolean variable.


matomo