In this article, we will cover 3 ways to check if the list is empty in Python.
To check if Python List is empty, we can write a condition if the length of the list is zero or not; or we can directly use the list reference along with not operator as a condition in if statement.
Table of Contents
Check if a List is Empty with not operator
We will initialize an empty list, and check programmatically if the list is empty or not using not operator and list reference.
myList = []
if not myList:
print(‘The list is empty.’)
else:
print(‘The list is not empty.’)
more info about not operator
The not operator negates the truth value of its operand. A true operand returns False. A false operand returns True.
>>> not True
False
>>> not False
True
More example of not operator
>>> not 0
True
>>> not 42
False
>>> not True
False
>>> not “”
True
>>> not “Hello”
False
>>> not []
True
>>> not [1, 2, 3]
False
>>> not {}
True
>>> not {“one”: 1, “two”: 2}
False
Check if a List is Empty using len() function
we will initialize an empty list, and check programmatically if the list is empty or not using len() function.
myList = []
if (len(myList) == 0):
print(‘The list is empty.’)
else:
print(‘The list is not empty.’)
more info about len()
- The len() function returns the number of items (length) in an object.
- The len() function takes a single argument, which can be
- sequence – string, bytes, tuple, list, range OR,
- collection – dictionary, set, frozen set
example of len()
languages = [‘Python’, ‘Java’, ‘JavaScript’]
# compute the length of languages
length = len(languages)
print(length) # Output: 3
Check if a List is Empty using list Comparison
myList = []
if (len(myList) == []):
print(‘The list is empty.’)
else:
print(‘The list is not empty.’)
Which is the fastest?
From our testing, we can see that the first method is not only 50% faster than method 2 and 75% faster than method 3.
It’s clearly the best method in terms of runtime performance.