Use math.isnan:
>>> import math
>>> x = float('nan')
>>> math.isnan(x)
True
W3Schools
w3schools.com › python › ref_math_isnan.asp
Python math.isnan() Method
The math.isnan() method checks whether a value is NaN (Not a Number), or not.
isnan() function in Python | methods in python | function ...
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check value is nan python - YouTube
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How to check for NaN values in Python - YouTube
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How to check for NaN NOT A NUMBER values - YouTube
Turing
turing.com › kb › nan-values-in-python
How to Check for NaN Values in Python?[With Examples]
The math module in Python provides the isnan() function, which can be used to check if a value is NaN. This method works only with floating-point values.
GeeksforGeeks
geeksforgeeks.org › python › check-for-nan-values-in-python
Check For NaN Values in Python - GeeksforGeeks
July 23, 2025 - NaN values are commonly encountered in data science and numerical computing when working with datasets that contain missing, undefined, or invalid values. The numpy.isnan() function is a simple way to check for NaN values in a NumPy array.
DataCamp
datacamp.com › home › tutorials › python › python nan: 4 ways to check for missing values in python
Python NaN: 4 Ways to Check for Missing Values in Python | DataCamp
February 15, 2024 - When dealing with missing values in Python, the approach largely depends on the data structure you're working with. NumPy's isnan() function is ideal for identifying NaNs in numeric arrays or single values, offering a straightforward and efficient solution.
NumPy
numpy.org › doc › 2.1 › reference › generated › numpy.isnan.html
numpy.isnan — NumPy v2.1 Manual
>>> import numpy as np >>> np.isnan(np.nan) True >>> np.isnan(np.inf) False >>> np.isnan([np.log(-1.),1.,np.log(0)]) array([ True, False, False])
Tutorial Gateway
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Python isnan
August 10, 2026 - The Python isnan function is one of the Mathematical functions used to check whether the given value is a valid number or not.
Digis
digiscorp.com › python-check-if-value-is-nan-a-complete-overview
Python Check If Value Is NaN: A Complete Overview
September 7, 2026 - For an individual numeric value in standard Python code, math.isnan() is usually the clearest option.
NumPy
numpy.org › doc › stable › reference › generated › numpy.isnan.html
numpy.isnan — NumPy v2.5 Manual
numpy.isnan(x, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature]) = <ufunc 'isnan'>#
Codecademy
codecademy.com › docs › python › math module › math.isnan()
Python | Math Module | math.isnan() | Codecademy
September 4, 2024 - In Python, the math.isnan() function returns True if the given value is NaN (not a number) and False if the value is a number.
Note.nkmk.me
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What is nan in Python (float('nan'), math.nan, np.nan) | note.nkmk.me
May 9, 2023 - Convert between bool (True/False) and other types in Python · As you can see with bool(), nan is evaluated as True. ... Use math.isnan() or np.isnan().
Educative
educative.io › answers › what-is-numpyisnan-in-python
What is numpy.isnan() in Python?
Python’s numpy.isnan() tests if an element is · NaN · Not a Number or not. It tests an array element-wise and returns Boolean values.
GeeksforGeeks
geeksforgeeks.org › python › python-math-library-isnan-method
Python math library | isnan() method - GeeksforGeeks
February 20, 2023 - Syntax : math.isnan(x) Parameters : x [Required] : It is any valid python data type or any number. Returns: Return type is boolean.
GeeksforGeeks
geeksforgeeks.org › python-math-library-isnan-method
Python math library | isnan() method | GeeksforGeeks
February 20, 2023 - Syntax : math.isnan(x) Parameters : x [Required] : It is any valid python data type or any number. Returns: Return type is boolean.
Towards Data Science
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5 Methods to Check for NaN values in in Python | Towards Data Science
February 23, 2021 - Learn this step by step with the interactive AI and Data Scientist roadmap. isna() in pandas library can be used to check if the value is null/NaN. It will return True if the value is NaN/null.
w3resource
w3resource.com › numpy › logic-functions › isnan.php
NumPy Logic functions: isnan() function - w3resource
May 2, 2026 - NumPy Logic functions: isnan() function, example - The isnan() function is used to test element-wise for NaN and return result as a boolean array.
Saturn Cloud
saturncloud.io › blog › efficiently-checking-if-arbitrary-object-is-nan-in-python-numpy-pandas
Efficiently Checking if Arbitrary Object is NaN in Python Numpy and Pandas | Saturn Cloud Blog
May 1, 2026 - In Python, the built-in math module provides a function called isnan() that can be used to check if a value is NaN.
Sentry
sentry.io › sentry answers › python › check for nan values in python
Check for NaN Values in Python Using math.isnan | Sentry
October 2, 2026 - Use the math.isnan function to check whether a float value is NaN in Python, with a robust implementation that handles non-numeric types using try-except
Medium
medium.com › @amit25173 › numpy-isnan-in-python-63b8c185331e
numpy.isnan in Python. If you think you need to spend $2,000… | by Amit Yadav | Medium
February 9, 2025 - If numpy.isnan returns True, it replaces the value with 0 (or any number you specify).
GeeksforGeeks
geeksforgeeks.org › numpy-isnan-python
numpy.isnan() in Python - GeeksforGeeks
March 8, 2024 - numpy.isnan() in Python · Last Updated : 08 Mar, 2024 · Comments · Improve · Suggest changes · Like Article · Like · Report · The numpy.isnan() function tests element-wise whether it is NaN or not and returns the result as a boolean array.