Inner join in Data Analysis Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to perform an inner join of two DataFrames on the 'id' column.

Data Analysis Python

result = df1.merge(df2, on=[1])

Drag options to blanks, or click blank then click option'

A'name'

B'age'

C'id'

D'date'

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column name that does not exist in both DataFrames.

Forgetting to put quotes around the column name.

The merge function joins two DataFrames on the specified column. Here, joining on 'id' matches rows with the same 'id' in both DataFrames.

2fill in blank

medium

Complete the code to perform an inner join and keep only rows with matching keys.

Data Analysis Python

joined = df1.merge(df2, on='id', how=[1])

Drag options to blanks, or click blank then click option'

A'inner'

B'left'

C'outer'

D'right'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'left' or 'right' which keep unmatched rows from one side.

Using 'outer' which keeps all rows from both DataFrames.

The how='inner' option keeps only rows with matching keys in both DataFrames.

3fill in blank

hard

Fix the error in the code to correctly perform an inner join on 'user_id'.

Data Analysis Python

result = df1.merge(df2, on=[1])

Drag options to blanks, or click blank then click option'

A'userid'

B'id'

C'userId'

D'user_id'

Attempts:

3 left

💡 Hint

Common Mistakes

Using a column name with wrong case or spelling.

Using a column name that exists only in one DataFrame.

The column name must exactly match in both DataFrames. Here, 'user_id' is the correct column name.

4fill in blank

hard

Fill both blanks to perform an inner join on 'order_id' and keep only matching rows.

Data Analysis Python

joined = df_orders.merge(df_customers, on=[1], how=[2])

Drag options to blanks, or click blank then click option'

A'order_id'

B'inner'

C'outer'

D'customer_id'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'customer_id' instead of 'order_id' as join key.

Using 'outer' join which keeps unmatched rows.

We join on 'order_id' and use how='inner' to keep only matching rows.

5fill in blank

hard

Fill all three blanks to perform an inner join on 'product_id', rename the joined column, and keep only matching rows.

Data Analysis Python

result = df1.merge(df2, on=[1], how=[2]).rename(columns=[3])

Drag options to blanks, or click blank then click option'

A'product_id'

B'inner'

C{'price_y': 'price'}

D'price_x'

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong join column.

Using 'outer' or other join types instead of 'inner'.

Not renaming the duplicate column causing confusion.

We join on 'product_id' with an inner join, then rename the 'price_y' column to 'price' for clarity.