In this tutorial, we will look at how to check if a list contains only numbers in Python with the help of some examples.
How to check if all list elements are numbers?

You can use a combination of the Python built-in isinstance()
and all()
function to check if a list contains only numbers. For instance, you can use the following steps to check if all elements in a list are integers in Python –
- In a list comprehension, for each element in the list, check if it’s an integer using the
isinstance()
function. - Apply the Python built-in
all()
function to returnTrue
only if all the items in the above list comprehension correspond toTrue
.
The following is the code to check if all elements in a list are integers or not.
# check if all elements in ls are integers all([isinstance(item, int) for item in ls])
Let’s take a look at an example.
# list of numbers ls = [1, 2, 3, 4] # check if list contains only numbers print(all([isinstance(item, int) for item in ls]))
Output:
True
We get True
as the output as all elements in the list ls
are integers.
Let’s take a look at another example.
# list of numbers and a string ls = [1, 2, 3, 4, 'cat'] # check if list contains only numbers print(all([isinstance(item, int) for item in ls]))
Output:
False
Here we get False
as the output because not all elements in the list ls
are integers. One element, “cat” in the list is a string.
Check if all items in a list of strings are numeric
If you, however, have a list of strings and want to check whether all the elements in the list are digits or not, you can use the following code.
# list of numeric strings ls = ["1", "2", "3", "4"] # check if list of string contains only numberic elements print(all([item.isdigit() for item in ls]))
Output:
True
Here we check whether each element in the list of strings, ls
is a numerical value or not using the string isdigit()
function. We get True
as the output as all the strings in the list ls
are numeric characters.
You might also be interested in –
- Python – Check if String Contains Only Numbers
- Python – Check List Contains All Elements Of Another List
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