In this tutorial, we will look at how to check if a string contains only letters and numbers in Python with the help of examples.
How to check if a string contains only letters and numbers?

You can use the string isalnum()
function to check if a string contains only letters (that is, alphabets) and/or numbers in Python. The following is the syntax –
# check if string s contains only alphanumeric characters s.isalnum()
It returns True
if all the characters in the string are alphanumeric (containing only alphabets and/or numbers). If any of the characters is not alphanumeric, it returns False
.
Let’s look at an example.
# create a string s = "Bunny123" # check if string contains only alphanumeric characters print(s.isalnum())
Output:
True
We get True
as the output. This is because all the characters in the string s
above are either letters or numbers.
Let’s look at another example.
# create a string s = "Bunny_123" # check if string contains only alphanumeric characters print(s.isalnum())
Output:
False
Here, we get False
as the output. This is because not all characters in the string s
above are alphanumeric. One of the characters in the string, “_” is neither an alphabet nor a digit.
For more on the string isalnum() function, refer to its documentation.
You might also be interested in –
- Python – Check If String Contains Only Letters
- Python – Check if String Contains Only Numbers
- Check If String Contains Only Certain Characters in Python
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