How to fill missing values in pandas?
Published on Aug. 22, 2023, 12:18 p.m.
You can fill missing values in pandas using the fillna()
method. fillna()
provides several options for how to fill the missing values. Here are a few examples:
- Fill with a specific value:
import pandas as pd
create a sample dataframe with missing values
df = pd.DataFrame({‘A’: [1, 2, None, 4], ‘B’: [5, 6, 7, None]})
fill missing values with 0
df = df.fillna(0)
print(df)
This will output a new DataFrame with all missing values replaced with 0:
A B
0 1.0 5.0
1 2.0 6.0
2 0.0 7.0
3 4.0 0.0
2. Fill with the mean value of the column:
fill missing values with mean of column
df = df.fillna(df.mean())
print(df)
This will output a new DataFrame with all missing values replaced with the mean value of the respective columns:
A B
0 1.0 5.0
1 2.0 6.0
2 2.333333 7.0
3 4.0 6.0
3. Forward fill missing values (propagate non-null values forward):
forward fill missing values
df = df.fillna(method=’ffill’)
print(df)
This will output a new DataFrame with all missing values filled with the previous non-null value in their respective columns:
A B
0 1.0 5.0
1 2.0 6.0
2 2.0 7.0
3 4.0 7.0
4. Backward fill missing values (propagate non-null values backward):
backward fill missing values
df = df.fillna(method=’bfill’)
print(df)
This will output a new DataFrame with all missing values filled with the next non-null value in their respective columns:
A B
0 1.0 5.0
1 2.0 6.0
2 4.0