Python String isdigit() Method

The isdigit() method is a built-in Python function that checks if all characters in a string are digits. This method returns True if each character in the string is a numeric digit (0-9) and False otherwise. Example:

a = "12345"
print(a.isdigit())  
b = "1234a5"
print(b.isdigit())

True
False

Explanation: In this example, a.isdigit() returns True because "12345" consists entirely of numeric characters, while b.isdigit() returns False due to the non-numeric character "a" in the string.

Syntax of isdigit()

s.isdigit()

Parameters: This method does not take any parameters

Returns:

• It returns True if every character in the string is a numeric digit (0-9).
• It returns False if there is any non-numeric character in the string.

Examples of isdigit()

Let's explore some examples of isdigit() method for better understanding.

Example 1: Here are example with a string containing only digits, a mixed-character string and an empty string.

# Only digits
print("987654".isdigit()) 
# Digits and alphabet
print("987b54".isdigit()) 
# Empty string
print("".isdigit())

True
False
False

Explanation:

• "987654".isdigit() returns True as it contains only numeric digits.
• "987b54".isdigit() returns False due to the non-digit character 'b'.
• "".isdigit() returns False because the string is empty.

Example 2: The isdigit() method can also be used to check numeric characters encoded in Unicode, such as the standard digit '1' and other Unicode representations of numbers.

# Unicode for '1'
a = "\u0031"  
print(a.isdigit()) 
# Devanagari digit for '1'
b = "\u0967"  
print(b.isdigit())

True
True

Explanation:

• "\u0031".isdigit() returns True as it represents the standard digit '1'.
• "\u0967".isdigit() returns True as it represents the Devanagari digit '1'.

Example 3: Here are example with Roman numerals, which are not recognized as digits.

print("I".isdigit())  
print("X".isdigit())  
print("VII".isdigit())  

False
False
False

Explanation: "I".isdigit(), "X".isdigit() and "VII".isdigit() all return False as Roman numerals are not recognized as digits by isdigit().

Related Articles:

• Python String isdecimal()
• Python String isnumeric() Method
• Python String isalpha()
• Python String isalnum()