How to Check for Nan Values
Better Stack Team
Updated on June 19, 2024
In pandas, you can check for NaN (Not a Number) values using the isna()
or isnull()
methods. These methods return a DataFrame of the same shape as the original DataFrame, where each element is True
if it's NaN and False
otherwise. Here's how you can do it:
import pandas as pd
import numpy as np
# Create a DataFrame with NaN values
data = {'A': [1, np.nan, 3], 'B': [np.nan, 5, np.nan], 'C': [7, 8, 9]}
df = pd.DataFrame(data)
# Check for NaN values using isna()
nan_values = df.isna()
print("DataFrame:")
print(df)
print("\\nNaN values:")
print(nan_values)
This will output:
DataFrame:
A B C
0 1.0 NaN 7
1 NaN 5.0 8
2 3.0 NaN 9
NaN values:
A B C
0 False True False
1 True False False
2 False True False
In this example, nan_values
is a DataFrame where each True
value indicates a NaN value in the corresponding position of the original DataFrame df
.