How to Check if a String Contains a Number in Python

John on June 04, 2021

In this tutorial, we will learn how to check if a string contains a number in Python.

Check Each Character with str.isdigit()

The first way we can approach solving this problem is to loop through and evaluate each character with the str.isdigit() function. If the character is indeed a number .isdigit() will return True.

string = 'Some t3xt'
result = False

for i in string:
  if str.isdigit(i):
    result = True
       
print(result)

True

To do the above operation in one line, use the Python any() function which returns True if anything in an iterable returns True.

string = 'Some t3xt'

print(any(str.isdigit(i) for i in string))

True

Check if String Contains a Number with map()

Instead of a for loop we can use the Python map() function, which will do the same job but with a cleaner syntax.

string = 'Some t3xt'

print(any(map(str.isdigit, string)))

True

If you prefer to use RegEx to evaluate strings, import the re package and use the .search() function. Pass an expression that will for a number in the string as the first argument and the string as the second like this:

import re

string = 'Some t3xt'

print(re.search(r'\d', string))

<re.Match object; span=(6, 7), match='3'>

If a RegEx match is found .search() will return a re.Match object, otherwise, None is returned.

Get Position of a Number in a String and the Value of the Number

The advantage of using the above method is that the re.Match object contains data about the position of the number found in the string and what that number is.

import re

string = 'Some t3xt'

result = re.search(r'\d', string)

print(result.group(0))
print(result.span())

3
(6,7)

group(0) returns the matching value and span() returns its position in the string.