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Python program to check whether a string contains a number or not
Python isdigit() function example: Here, we are going to learn how to check whether a string contains only digits or not i.e. string contains only number or not?
By IncludeHelp Last updated : February 25, 2024
Problem statement
Given a string and we have to check whether it contains only digits or not in Python.
Example
Input:
str1 = "8789"
str2 = "Hello123"
str3 = "123Hello"
str4 = "123 456" #contains space
# function call
str1.isdigit()
str2.isdigit()
str3.isdigit()
str4.isdigit()
Output:
True
False
False
False
Checking string contains a number or not
To check that a string contains only digits (or a string has a number) – we can use isdigit() function, it returns true, if all characters of the string are digits.
Syntax
string.isdigit()
Python code to check whether a strings contains a number or not
# python program to check whether a string
# contains only digits or not
# variables declaration & initializations
str1 = "8789"
str2 = "Hello123"
str3 = "123Hello"
str4 = "123 456" #contains space
# checking
print("str1.isdigit(): ", str1.isdigit())
print("str2.isdigit(): ", str2.isdigit())
print("str3.isdigit(): ", str3.isdigit())
print("str4.isdigit(): ", str4.isdigit())
# checking & printing messages
if str1.isdigit():
print("str1 contains a number")
else:
print("str1 does not contain a number")
if str2.isdigit():
print("str2 contains a number")
else:
print("str2 does not contain a number")
if str3.isdigit():
print("str3 contains a number")
else:
print("str3 does not contain a number")
if str4.isdigit():
print("str4 contains a number")
else:
print("str4 does not contain a number")
Output
str1.isdigit(): True
str2.isdigit(): False
str3.isdigit(): False
str4.isdigit(): False
str1 contains a number
str2 does not contain a number
str3 does not contain a number
str4 does not contain a number
To understand the above program, you should have the basic knowledge of the following Python topics:
Python String Programs »