if not a:
print("List is empty")
Using the implicit booleanness of the empty list is quite Pythonic.
Top answer 1 of 16
7312
if not a:
print("List is empty")
Using the implicit booleanness of the empty list is quite Pythonic.
2 of 16
1556
The Pythonic way to do it is from the PEP 8 style guide.
For sequences, (strings, lists, tuples), use the fact that empty sequences are false:
# Correct: if not seq: if seq: # Wrong: if len(seq): if not len(seq):
GeeksforGeeks
geeksforgeeks.org › python › python-check-if-list-empty-not
Check if a list is empty or not in Python - GeeksforGeeks
October 24, 2024 - We can also use len() function to see if a list is empty by checking if its length is zero. ... Explanation: len(a) returns 0 for an empty list. Lists can be directly evaluated in conditions. Python considers an empty list as False.
How do I check if this list is "empty"?
Well there are a few ways you could deal with this. First would be to check if userInput is an empty string before converting it to a list. Another possibility would be to filter the list to remove all empty strings, eg via a list comprehension. Or you could do the filtering inside the loop you already have that converts to integers. Or, again inside that loop, you could use a counter variable to keep track of how many integers you've converted, and print an error afterwards if it's 0. And so on. The main thing here is that you should get away from thinking about how to code something, but first work out what the steps should be, and only then code it. More on reddit.com
7
1
December 8, 2022!! vs ==0 when checking if array is empty
Why is this downvoted? It's literally the 'learnjavascript' sub. More on reddit.com
63
94
June 30, 2024Videos
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Quora
quora.com › How-do-I-check-if-an-array-is-empty-in-Python
How to check if an array is empty in Python - Quora
Answer (1 of 12): I am going to assume you are talking about lists (Python does have arrays, but they are very different to lists). Three ways : 1 Test the truthiness If you know the item is a list you do : [code]if not my_list: print(‘List is empty’) [/code]Empty containers (lists,sets,t...
Built In
builtin.com › articles › python-check-if-list-is-empty
Python Check if a List Is Empty: A Guide | Built In
November 7, 2024 - The most common approach is using the truth value testing method with the not operator, but you can also check lists using the len() function and the == operator. Here’s how each method works.
Better Stack
betterstack.com › community › questions › how-to-check-if-list-is-empty-in-python
How do I check if a list is empty in Python? | Better Stack Community
January 26, 2023 - You can check if a list is empty by using the len() function to check the length of the list.
Curict
en.curict.com › item › 9a › 9a5983d.html
Checking if a Python list is empty
Since None is also considered False, if you want to strictly compare None and an empty list, you can use the “is None” operator to check. ... # Checking for an empty list considering None if emptyList is None: print('It is None') elif not emptyList: print('The list is empty')
Python Morsels
pythonmorsels.com › checking-for-an-empty-list-in-python
Checking for an empty list in Python - Python Morsels
August 20, 2024 - Many Python users prefer to check for an empty list by evaluating the list's truthiness. A non-empty list is truthy, and an empty list is falsey. This if statement's condition didn't pass because the list was empty, and therefore falsey:
w3resource
w3resource.com › python-exercises › numpy › python-numpy-exercise-95.php
NumPy: Check whether the numpy array is empty or not - w3resource
August 29, 2025 - # Importing the NumPy library and aliasing it as 'np' import numpy as np # Creating a NumPy array 'x' containing integers [2, 3] x = np.array([2, 3]) # Creating an empty NumPy array 'y' y = np.array([]) # Printing the size of array 'x' # As 'x' contains 2 elements, its size is 2 print(x.size) # Printing the size of array 'y' # 'y' is an empty array, so its size is 0 print(y.size) ... print(x.size): Print the size of array 'x' using the size attribute.
freeCodeCamp
freecodecamp.org › news › how-to-check-if-a-list-is-empty-in-python
Python isEmpty() equivalent – How to Check if a List is Empty in Python
April 19, 2023 - Comparing the list to an empty list. The not operator in Python is used for logical negation. Here's an example: x = True y = False print(not x) # Output: False print(not y) # Output: True · not returns true when an operand is false, and false if an operand is true. You can check if a collection is empty using the logic above.
Vultr
docs.vultr.com › python › examples › check-if-a-list-is-empty
Python Program to Check If a List is Empty | Vultr Docs
December 6, 2024 - Here, if not my_list effectively checks if my_list is empty and prints "List is empty." Otherwise, it prints "List is not empty." Compare the list directly to an empty list [] using the == operator. This method makes the check explicit and clear in the code.
Reddit
reddit.com › r/learnpython › how do i check if this list is "empty"?
r/learnpython on Reddit: How do I check if this list is "empty"?
December 8, 2022 -
I'm completely stumped on a computer science assignment because our lecturer has given us zero information. We're supposed to have the user input a list and check if the list is in decreasing order and print a suitable message if it is. That part works fine. However, if the list is "empty" (I'll explain the quotations in a second) then it should print the list is empty.
The problem is that, according to our brief we're supposed to use .split(",") in order to allow the user to separate their numbers with commas. The problem lies in the fact that even if a user hits enter without inputting anything, the list is still '1' long with just an empty string. I've been scouring the web to find out how to check if a list is empty. But all the tutorials have so far just been in relation to actually empty lists (as in, list = []). One did use the all() function to check that all items in the list were strings, which did work and let me print that the list is empty, but broke the original function. Could someone please help me I'm tearing my hair out with this.
--
def checkOrder():
# checks, etc.
integer_list = []
listLength = len(integer_list)
increasing = 0
decreasing = 0
singleValue = 0
# Converting inputted numbers into a split list
userInput = input("Please enter your numbers seperated by a comma (,):")
inputtedStrings = userInput.split(",")
for number in inputtedStrings:
inputtedIntegers = int(number)
integer_list.append(inputtedIntegers)
# Enumerating list
for i, val in enumerate(integer_list[:-1]):
if val <= integer_list[i+1]:
increasing = 1
elif val >= integer_list[i+1]:
decreasing = 1
# Check for a single value
if len(integer_list) == 1:
singleValue = 1
if len(integer_list) == 1 and
print("The list is empty.")
if increasing == 1:
print("The numbers are in increasing order.")
elif decreasing == 1 or singleValue == 1:
print("The numbers are in decreasing order.")
checkOrder()
--
Top answer 1 of 5
8
Well there are a few ways you could deal with this. First would be to check if userInput is an empty string before converting it to a list. Another possibility would be to filter the list to remove all empty strings, eg via a list comprehension. Or you could do the filtering inside the loop you already have that converts to integers. Or, again inside that loop, you could use a counter variable to keep track of how many integers you've converted, and print an error afterwards if it's 0. And so on. The main thing here is that you should get away from thinking about how to code something, but first work out what the steps should be, and only then code it.
2 of 5
3
arr = [''] print(any(arr)) # False any and all are pretty useful built-in functions for iterative boolean checks.
Sentry
sentry.io › sentry answers › python › check if a list is empty in python
Check if a list is empty in Python | Sentry
March 15, 2023 - The Problem How do I check if a list is empty in Python? The Solution The Python style guide, PEP-8, recommends checking whether a list (or other sequence) is…
Spark By {Examples}
sparkbyexamples.com › home › python › check if the list is empty in python
Check if the List is Empty in Python - Spark By {Examples}
May 31, 2024 - All the above methods explained to check if the list is empty in Python don’t work with NumPy hence we have to use np.size to get the size of an array, if it is empty it returns 0 which can be used to check the array is empty or not.
Medium
pavolkutaj.medium.com › how-to-check-if-a-list-dict-or-set-is-empty-in-python-as-per-pep8-35d8c64d07d0
How to Check if a List, Dict or Set is Empty in Python as per PEP8 | by Pavol Z. Kutaj | Medium
September 7, 2023 - in effect, it is saying that ... · The canonical way of knowing if an array in C is empty is by dereferencing the first element and seeing if it is null, assuming an array that is nul-terminated....
IncludeHelp
includehelp.com › python › how-to-check-whether-a-numpy-array-is-empty-or-not.aspx
How to check whether a NumPy array is empty or not?
May 26, 2023 - The numpy.any() method checks whether any array element along a given axis evaluates to True. If the given array is not empty it returns True; False, otherwise. numpy.any(a, axis=None, out=None, keepdims=<no value>, *, where=<no value>) Consider the below Python program to check NumPy array ...
W3Schools
w3schools.com › python › python_arrays.asp
Python Arrays
Note: Python does not have built-in support for Arrays, but Python Lists can be used instead. ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: sales@w3schools.com
Python.org
discuss.python.org › python help
How to check if a dictionary element is an array - Python Help - Discussions on Python.org
July 19, 2024 - How do I make sure that [0] exists before grabbing ‘icon’ from it · Now, regarding your question, here is an example that hopefully helps you to understand the concept. Note that you do not need to explicitly define the icon string in brackets as per your query.
Top answer 1 of 10
268
Supposing your array is $errors, just check to see if the count of elements is zero.
if [ ${#errors[@]} -eq 0 ]; then
echo "No errors, hooray"
else
echo "Oops, something went wrong..."
fi
2 of 10
65
I generally use arithmetic expansion in this case:
if (( ${#a[@]} )); then
echo not empty
fi
NumPy
numpy.org › doc › stable › user › absolute_beginners.html
NumPy: the absolute basics for beginners — NumPy v2.4 Manual
If the element you’re looking for doesn’t exist in the array, then the returned array of indices will be empty.
Flexiple
flexiple.com › python › check-if-list-is-empty-python
Python isEmpty() equivalent – How to Check if a List is Empty in Python - Flexiple - Flexiple
March 14, 2022 - Check if a list is empty in Python by using the len() function or compare the list directly to an empty list.