Pandas: Replace all the NaN values with Zero's in a column of a dataframe
Write a Pandas program to replace all the NaN values with Zero's in a column of a dataframe.
Sample data:
Original DataFrame
attempts name qualify score
0 1 Anastasia yes 12.5
1 3 Dima no 9.0
2 2 Katherine yes 16.5
3 3 James no NaN
4 2 Emily no 9.0
5 3 Michael yes 20.0
6 1 Matthew yes 14.5
7 1 Laura no NaN
8 2 Kevin no 8.0
9 1 Jonas yes 19.0
New DataFrame replacing all NaN with 0:
attempts name qualify score
0 1 Anastasia yes 12.5
1 3 Dima no 9.0
2 2 Katherine yes 16.5
3 3 James no 0.0
4 2 Emily no 9.0
5 3 Michael yes 20.0
6 1 Matthew yes 14.5
7 1 Laura no 0.0
8 2 Kevin no 8.0
9 1 Jonas yes 19.0
Sample Solution :
Python Code :
import pandas as pd
import numpy as np
exam_data = {'name': ['Anastasia', 'Dima', 'Katherine', 'James', 'Emily', 'Michael', 'Matthew', 'Laura', 'Kevin', 'Jonas'],
'score': [12.5, 9, 16.5, np.nan, 9, 20, 14.5, np.nan, 8, 19],
'attempts': [1, 3, 2, 3, 2, 3, 1, 1, 2, 1],
'qualify': ['yes', 'no', 'yes', 'no', 'no', 'yes', 'yes', 'no', 'no', 'yes']}
df = pd.DataFrame(exam_data)
print("Original DataFrame")
print(df)
df = df.fillna(0)
print("\nNew DataFrame replacing all NaN with 0:")
print(df)
Sample Output:
Original DataFrame attempts name qualify score 0 1 Anastasia yes 12.5 1 3 Dima no 9.0 2 2 Katherine yes 16.5 3 3 James no NaN 4 2 Emily no 9.0 5 3 Michael yes 20.0 6 1 Matthew yes 14.5 7 1 Laura no NaN 8 2 Kevin no 8.0 9 1 Jonas yes 19.0 New DataFrame replacing all NaN with 0: attempts name qualify score 0 1 Anastasia yes 12.5 1 3 Dima no 9.0 2 2 Katherine yes 16.5 3 3 James no 0.0 4 2 Emily no 9.0 5 3 Michael yes 20.0 6 1 Matthew yes 14.5 7 1 Laura no 0.0 8 2 Kevin no 8.0 9 1 Jonas yes 19.0
Explanation:
The above code creates a Pandas DataFrame called ‘df’ from a dictionary called ‘exam_data’ that contains information about students and their exam scores. Some of the students have missing scores, which are represented as np.nan values.
df = df.fillna(0): The fillna() method is then used to fill in these missing values with 0.
Finally the resulting DataFrame is printed to the console using print() function.
Python-Pandas Code Editor:
Have another way to solve this solution? Contribute your code (and comments) through Disqus.
Previous: Write a Pandas program to select a row of series/dataframe by given integer index.
Next: Write a Pandas program to convert index in a column of the given dataframe.
What is the difficulty level of this exercise?
Test your Programming skills with w3resource's quiz.
- Weekly Trends and Language Statistics
- Weekly Trends and Language Statistics