Python String isdigit()

Summary: in this tutorial, you’ll learn how to use the Python string isdigit() method to determine if all characters in a string are digits.

Introduction to the Python String isdigit() method

The string isdigit() method returns True if:

1. All characters in the string are digits and
2. The string has at least one character.

Otherwise, it returns False.

The following shows the syntax if the string isdigit() method:

str.isdigit()Code language: CSS (css)

The isdigit() method returns True if the string contains solely the digits (0-9). If a string contains a decimal point, minus, or plus sign, the isdigit() returns False.

Note that the isdigit() also returns True for a string that contains superscript like ’10²’.

Python String isdigit() method examples

The following example uses the isdigit() method to check if the all characters in a string are digits:

quantity = '100'
print(quantity.isdigit())Code language: PHP (php)

Output:

TrueCode language: PHP (php)

The following example returns False:

price = '9.99'
print(price.isdigit())Code language: PHP (php)

Output:

False    Code language: PHP (php)

The following examples returns True because the Unicode character for 0 and 2 are digits:

x = "\u0030"  # unicode for 0
y = "\u00B2"  # unicode for ²

print(x.isdigit())
print(y.isdigit())Code language: PHP (php)

Output:

True
TrueCode language: PHP (php)

The following example returns False because the string is empty:

empty = ''
print(empty.isdigit())Code language: PHP (php)

Output:

False    Code language: PHP (php)

Summary

• Use the Python string isdigit() method to check if all characters in a string are digits.