Pandas: Group by the first column and get second column as lists in rows
Write a Pandas program to group by the first column and get second column as lists in rows.
Sample Solution :
Python Code :
import pandas as pd
df = pd.DataFrame( {'col1':['C1','C1','C2','C2','C2','C3','C2'], 'col2':[1,2,3,3,4,6,5]})
print("Original DataFrame")
print(df)
df = df.groupby('col1')['col2'].apply(list)
print("\nGroup on the col1:")
print(df)
Sample Output:
Original DataFrame col1 col2 0 C1 1 1 C1 2 2 C2 3 3 C2 3 4 C2 4 5 C3 6 6 C2 5 Group on the col1: col1 C1 [1, 2] C2 [3, 3, 4, 5] C3 [6] Name: col2, dtype: object
Python-Pandas Code Editor:
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