In this article, we will discuss different ways to check if a string contains a number or not in Python.
Table of Contents
Suppose we have two strings,
"The hidden number is 22 today." "The is sample text."
The first string contains a number, whereas the second string does not contain any number. We want to detect this using code. There are different ways to check if a string contains a number or digit. Let’s discuss them one by one
Check if a string contains a number using any() and List Comprehension
We can iterate over all characters of a string one by one using the list comprehension and a build a boolean list. During iteration, for each character we can check if it is a digit or not. If yes, then add True in the list, else add False. Then using the any() function, we can check if the list contains any True value. If yes, then it means the string contains a number. For example,
sampleStr = "The hidden number is 22 today."
# Check if string contains any number
result = any([ch.isdigit() for ch in sampleStr])
if result:
print('Yes, string contains a number')
else:
print('No, string does not contain any number')
Output:
Yes, string contains a number
It confirmed that the string contains a number.
Check if a string contains a number using Regex
The search() function of the regex module accepts a pattern and a string as arguments. Then it looks into the given string and tries to find a match to the given pattern. If match is found, then it returns a Match object, otherwise returns None. We can use the regex pattern “[0-9]” with the search() function to look for any digit in the string. For example,
import re
sampleStr = "The hidden number is 22 today."
# Check if string contains any number
result = re.search("[0-9]", sampleStr)
if result:
print('Yes, string contains a number')
else:
print('No, string does not contain any number')
Output:
Yes, string contains a number
It confirmed that the string contains a number.
Check if a string contains a number using any() & map()
We can pass the str.isdigit and a given string as arguments in the map() function. It will apply the isdigit() function to each character of the string and returns an iterator pointing to the returned boolean values. Pass that to the any() function to check if it contains any True value. If yes, then it means the string contains a number. For example,
sampleStr = "The hidden number is 22 today."
# Check if string contains any number
result = any(map(str.isdigit, sampleStr))
if result:
print('Yes, string contains a number')
else:
print('No, string does not contain any number')
Output:
Yes, string contains a number
It confirmed that the string contains a number.
Summary
We learned different ways to check if a string contains a number or not in Python. Happy Learning.