Python empty list - How to check if a list is empty
Python list may be empty and there are many ways to check if a list is empty or not. The below code follows the standard Python coding convention (PEP).
a = [2, 3, 5] b =  if a: print('a is Good') else: print('a is Bad') # a is Good if b: print('b is Good') else: print('b is Bad') # b is Bad
It is recommended that you simply use
if ... statement to check a list is empty.
In fact, you can check if an object is list by counting the number of items. If it is 0, the list may be empty.
b =  if 0 < len(b): print('b is Good') else: print('b is Bad') # b is Bad
But this is not pythonic and not recommended.
Index of empty list
Empty list has no index.
a =  b = a # IndexError: list index out of range
Compare empty lists
In Python, empty lists are the same.
a =  b =  if a == b: print('a is b.') else: print('a is not b.') # a is b.
But ids of them are completely different. Python id represents the identity or memory address of an object. As you can see, ids of empty lists are different.
a =  b =  print(id(a)) # 4529691520 print(id(b)) # 4529692224
As explained in this post, the same values (int, float, ...) have the same ids but it is not true for lists and empty lists.