DataFrame Merge Key Mismatches

DataFrame Merge Key Mismatches

Mismatched keys when merging data frames is one of the most frequent errors you’ll run into.
In this example, we try to merge two dataframes where the customer ID columns had different names ("customer_id" vs "CustomerID"). If you try to merge, you’ll run into a KeyError exception:
# Create sample dataframes
sales_df = pd.DataFrame({
    'customer_id': [101, 102, 103, 104],
    'sale_amount': [1500, 2300, 1800, 3200]
})

customer_df = pd.DataFrame({
    'CustomerID': [101, 102, 103, 105],  # Note the different column name and slightly different data
    'customer_name': ['Alice', 'Bob', 'Charlie', 'Eve']
})

try:
    # This will raise an error
    merged_df = sales_df.merge(customer_df, left_on='customer_id', right_on='customer_id')
except KeyError as e:
    print("KeyError:", e)

for more :https://cuty.io/9xrZvgJmR