Pandas: Merge datasets and check uniqueness

Last update on May 01 2025 12:54:22 (UTC/GMT +8 hours)

69. Merge Datasets and Check Uniqueness

Write a Pandas program to merge datasets and check uniqueness.

Sample Solution :

Python Code :

import pandas as pd
df = pd.DataFrame({
    'Name': ['Alberto Franco','Gino Mcneill','Ryan Parkes', 'Eesha Hinton', 'Syed Wharton'],
    'Date_Of_Birth ': ['17/05/2002','16/02/1999','25/09/1998','11/05/2002','15/09/1997'],
    'Age': [18.5, 21.2, 22.5, 22, 23]
})
print("Original DataFrame:")
print(df)
df1 = df.copy(deep = True)
df = df.drop([0, 1])
df1 = df1.drop([2])
print("\nNew DataFrames:")
print(df)
print(df1)
print('\n"one_to_one”: check if merge keys are unique in both left and right datasets:"')
df_one_to_one = pd.merge(df, df1, validate = "one_to_one")
print(df_one_to_one)
print('\n"one_to_many” or “1:m”: check if merge keys are unique in left dataset:')
df_one_to_many = pd.merge(df, df1, validate = "one_to_many")
print(df_one_to_many)
print('“many_to_one” or “m:1”: check if merge keys are unique in right dataset:')
df_many_to_one = pd.merge(df, df1, validate = "many_to_one")
print(df_many_to_one)

Sample Output:

Original DataFrame:
             Name Date_Of_Birth    Age
0  Alberto Franco     17/05/2002  18.5
1    Gino Mcneill     16/02/1999  21.2
2     Ryan Parkes     25/09/1998  22.5
3    Eesha Hinton     11/05/2002  22.0
4    Syed Wharton     15/09/1997  23.0

New DataFrames:
           Name Date_Of_Birth    Age
2   Ryan Parkes     25/09/1998  22.5
3  Eesha Hinton     11/05/2002  22.0
4  Syed Wharton     15/09/1997  23.0
             Name Date_Of_Birth    Age
0  Alberto Franco     17/05/2002  18.5
1    Gino Mcneill     16/02/1999  21.2
3    Eesha Hinton     11/05/2002  22.0
4    Syed Wharton     15/09/1997  23.0

"one_to_one”: check if merge keys are unique in both left and right datasets:"
           Name Date_Of_Birth    Age
0  Eesha Hinton     11/05/2002  22.0
1  Syed Wharton     15/09/1997  23.0

"one_to_many” or “1:m”: check if merge keys are unique in left dataset:
           Name Date_Of_Birth    Age
0  Eesha Hinton     11/05/2002  22.0
1  Syed Wharton     15/09/1997  23.0
“many_to_one” or “m:1”: check if merge keys are unique in right dataset:
           Name Date_Of_Birth    Age
0  Eesha Hinton     11/05/2002  22.0
1  Syed Wharton     15/09/1997  23.0

For more Practice: Solve these Related Problems:

Write a Pandas program to merge two DataFrames on a common key and then check if the key is unique in both datasets.
Write a Pandas program to perform a merge and then identify duplicate merge keys by comparing the resulting DataFrame's index.
Write a Pandas program to merge two DataFrames with a one-to-many relationship and then validate the merge by counting rows.
Write a Pandas program to merge datasets and then output the number of unique keys from each side to confirm one-to-one matching.

Go to:

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Python-Pandas Code Editor:

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