Strings can contain all kinds of text: numbers, alphabets, Roman numerals, even hexadecimal values. But what if you needed to know whether or not a string only contains numbers? This can be done using the `isdigit()` built-in method in Python. The illustration below shows how the `isdigit()` method works.

Now that we know what this method does, let’s look at its signature.

# Syntax

## Parameters

This is an in-built method of strings and does not require any parameter to be passed. 

## Return Value

It returns a boolean value of `true` or `false` depending on if the string only contains digits and is not empty. 

>**Note:** The method does not recognize currency values, fractions, or Roman numerals as digits.

The code snippet below shows how to call this method. `str` is the string on which the method is called.

# Examples

Now that we know how this method works, let’s see how we can use it.

# This should return true as the string only contains integers
numeric_str = "101202303"
print(numeric_str.isdigit())

# This should return false as the string contains alphabets
alphanumeric_str = "10120A2303"
print(alphanumeric_str.isdigit())

# This should return false as the string contains the dollar currency sign
currency_str = "$10"
print(currency_str.isdigit())

# This should return false as the string is a fraction
fraction_str = "2/3"
print(fraction_str.isdigit())

What is the isdigit() function in Python?

The isdigit() method in Python checks if a string only contains digits, returning true or false.