# Convert nan value to zero in NumPy array

Learn, how to convert nan value to zero in NumPy array? By Pranit Sharma Last updated : October 09, 2023

NumPy is an abbreviated form of Numerical Python. It is used for different types of scientific operations in python. Numpy is a vast library in python which is used for almost every kind of scientific or mathematical operation. It is itself an array which is a collection of various methods and functions for processing the arrays.

While creating a DataFrame or importing a CSV file, there could be some NaN values in the cells. NaN values mean "Not a Number" which generally means that there are some missing values in the cell.

## Problem statement

Suppose we are given a NumPy array with some nan values and we want to replace these nan values with zeroes.

## Converting nan value to zero

For this purpose, we will use the isnan() method which produces a bool array indicating where the NaN values are. A boolean array can be used to index an array of the same shape. We will use it as a mask.

Let us understand with the help of an example,

## Python program to convert nan value to zero in NumPy array

```# Import numpy
import numpy as np

# Creating an array
arr = np.array([np.nan,0,5,np.nan,9,0,4,np.nan,8])

# Display original array
print("Original Array:\n",arr,"\n")

# Assigning 0 in place of nan values
arr[np.isnan(arr)] = 0

# Display result
print("Result:\n",arr,"\n")
```

### Output

The output of the above program is: