.isdigit()

The .isdigit() method under the string class checks if all the elements in the string are digits; applicable elements also include special cases like superscript digits (¹, ², ³, etc.). The method returns True in the mentioned cases and False otherwise.

This method is commonly used in input validation, data cleaning, and parsing operations where it is necessary to ensure that certain fields - like IDs, phone numbers (without formatting), or user-entered data - consist solely of digits. This method helps avoid errors that might occur from converting non-numeric strings to integers.

Syntax

string.isdigit()

In the syntax, string needs to be replaced with the name of the string on which the .isdigit() method is to be called.

Return value:

The method returns True if all the characters in a string are digits and False otherwise.

Example 1: Basic Usage of .isdigit()

This example uses the .isdigit() method to check if the given strings only contains digits:

my_string1 = "123"
my_string2 = "123AA"

print(my_string1.isdigit())
print(my_string2.isdigit())

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The output for the example will be:

True
False

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Example 2: Using .isdigit() on a String with Letters

This example uses the .isdigit() method on a string containing alphabetical characters:

text = "123abc"

print(text.isdigit())

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The output for the example will be:

False

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Codebyte Example: Using .isdigit() on a String with Special Characters

This codebyte example uses the .isdigit() method on a string containing special characters like !, -, \, and n:

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Since these special characters are not considered digits, the output for the example will be False.

Frequently Asked Questions

1. What is the difference between .isdigit() and .isnumeric() in Python?

Both .isdigit() and .isnumeric() return True for digit characters. However, .isnumeric() recognizes a broader set of numeric characters, including fractions, subscripts, superscripts, and other Unicode characters representing numbers. For example, the Unicode character \u00B2 (superscript 2) is considered numeric but not a digit.

2. What is the difference between .isdigit() and .isdecimal() in Python?

.isdecimal() is more restrictive than .isdigit(). It only returns True for characters that are strictly decimal numbers (0–9). In contrast, .isdigit() includes characters like superscripts.

3. Does .isdigit() work for floats?

No, .isdigit() returns False for strings representing float numbers because of the presence of a decimal point, which is not considered a digit.