Performing a left join between two DataFrames in Pandas

Last update on December 21 2024 07:41:37 (UTC/GMT +8 hours)

Pandas: Custom Function Exercise-3 with Solution

Write a Pandas program that performs a left join of two DataFrames.

This exercise demonstrates a left join of two DataFrames, including all rows from the left DataFrame and matching rows from the right.

Sample Solution :

Code :

import pandas as pd

# Create two sample DataFrames
df1 = pd.DataFrame({
    'ID': [1, 2, 3],
    'Name': ['Selena', 'Annabel', 'Caeso']
})

df2 = pd.DataFrame({
    'ID': [2, 3, 4],
    'Age': [25, 30, 22]
})

# Perform a left join on the 'ID' column
left_joined_df = pd.merge(df1, df2, on='ID', how='left')

# Output the result
print(left_joined_df)

Output:

   ID     Name   Age
0   1   Selena   NaN
1   2  Annabel  25.0
2   3    Caeso  30.0               

Explanation:

• Created two DataFrames df1 and df2.
• Used pd.merge() with how='left' to perform a left join.
• The result includes all rows from the left DataFrame and only the matching rows from the right DataFrame.

Python-Pandas Code Editor:

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