# Python math.isnan() Method

Musfirah Waseem Jan 30, 2023

Python `math.isnan()` method is used to check whether the specified number is `NaN` (not a number) or not.

## Syntax

``````math.isnan(x)
``````

## Parameters

`x` The required positive or negative number to check.

## Returns

The return type of this method is a Boolean value. `True` is returned if `x` is a `NaN` (not a number); otherwise, `False`.

## Example Code: Use of the `math.isnan()` Method

Example Code:

``````import math

x = 100
value = math.isnan(x)
print(f"Is {x} not a valid number? {value}")

x = math.pi
value = math.isnan(x)
print(f"Is {x} not a valid number? {value}")

x = -98.67
value = math.isnan(x)
print(f"Is {x} not a valid number? {value}")

x = math.inf
value = math.isnan(x)
print(f"Is {x} not a valid number? {value}")

value = math.isnan((float("nan")))
print(f"Is NaN not a valid number? {value}")
``````

Output:

``````Is 100 not a valid number? False
Is 3.141592653589793 not a valid number? False
Is -98.67 not a valid number? False
Is inf not a valid number? False
Is NaN not a valid number? True
``````

Note that the above code shows how we can use this method.

Musfirah is a student of computer science from the best university in Pakistan. She has a knack for programming and everything related. She is a tech geek who loves to help people as much as possible.