Python String isdigit() Method

The String isdigit() method returns True if the string is not empty and all the characters are digits. Otherwise, it returns False.

Syntax

my_string.isdigit()

isdigit() Parameters

Python String isdigit() method does not take any parameters.

isdigit() Return Value

Python String isdigit() method returns:

• True if ALL characters in the string are digits.
• False if AT LEAST ONE character is NOT a digit.

Examples

Example 1: Check if a String is digit with isdigit()

The isdigit() method returns True if all characters in the string are digits.

my_str = '123'
result = my_str.isdigit()
print(result) # Output: True

output

True

The isdecimal() method returns False if at least one character is not a digit.

For example, string of a float point number is not digit:

my_str = '123.456'
result = my_str.isdigit()
print(result) # Output: False

output

False

For example, string of number with thousands separator is not digit:

my_str = '1,234,567'
result = my_str.digit()
print(result) # Output: False

output

False

For example, empty string is not digit:

my_str = ''
result = my_str.isdigit()
print(result) # Output: False

output

False

Example 2: Check if a String with Unicode Digit Characters is digit with isdecimal()

Unicode characters, like U+0660 (Arabic-Indic Digit Zero), subscripts and superscripts, are also considered as digits.

my_str1 = '\u0660'     
my_str2 = '\u00B23455' # my_str2 = '²3455'
my_str3 = '\u20823455' # my_str2 = '₂3455'

print(my_str1.isdigit()) # Output: True
print(my_str2.isdigit()) # Output: True
print(my_str3.isdigit()) # Output: True

output

True
True
True

Special Unicode characters like circled digits ⑥ are also considered as digits.

my_str = '\u2465' # Special Unicode ⑥
print(my_str.isdigit()) # Output: True

output

True

But not all Unicode characters are valid digits!

For example, Vulgar Fractions are not digits!

my_str = '\u00BD'      # my_str2 = '½'

print(my_str.isdigit()) # Output: False

output

False

isdigit() method vs isdecimal() method vs isnumeric() method

The main difference between the isdigit(), isdecimal() and isnumeric() methods is that:

• isdigit() method supports Decimals, Subscripts, Superscripts

• isdecimal() method supports only Decimal Number

• isnumeric() method supports Digits, Vulgar Fractions, Subscripts, Superscripts, Roman Numerals, Currency Numerators.

Example with '123' as String:

print('123'.isdecimal())        # Output True
print('123'.isdigit())          # Output True
print('123'.isnumeric())        # Output True

output

True
True
True

Example with Superscript Two '²' (that is '\u00b2') as String:

print('\u00b2'.isdecimal())     # Output False
print('\u00b2'.isdigit())       # Output True
print('\u00b2'.isnumeric())     # Output True

output

False
True
True

Example with Vulgar Two '⅓' (that is '\u2153') as String:

print('\u2153'.isdecimal())     # Output False
print('\u2153'.isdigit())       # Output False
print('\u2153'.isnumeric())     # Output True

output

False
False
True