Stack and unstack in Data Analysis Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to stack the columns of the DataFrame into a Series.

Data Analysis Python

stacked = df.[1]()

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

Aunstack

Bpivot

Cstack

Dmelt

Attempts:

3 left

💡 Hint

Common Mistakes

Using unstack instead of stack.

Using pivot which reshapes data differently.

Using melt which creates a long DataFrame, not a Series.

The stack() method compresses columns into a single Series with a MultiIndex.

2fill in blank

medium

Complete the code to unstack the last level of the index in the Series.

Data Analysis Python

unstacked = stacked.[1]()

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

Astack

Bunstack

Creset_index

Dpivot_table

Attempts:

3 left

💡 Hint

Common Mistakes

Using stack instead of unstack.

Using reset_index which flattens the index but does not pivot.

Using pivot_table which requires specific arguments.

The unstack() method pivots the innermost index level to columns.

3fill in blank

hard

Fix the error in the code to stack only the level named 'year' in the DataFrame.

Data Analysis Python

stacked = df.[1](level='year')

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

Astack

Bmelt

Cpivot

Dunstack

Attempts:

3 left

💡 Hint

Common Mistakes

Using unstack with level argument which expands instead of compresses.

Using pivot which does not accept level argument.

Using melt which reshapes differently.

The stack() method accepts a level argument to stack only that index level.

4fill in blank

hard

Fill both blanks to create a DataFrame from a stacked Series and then stack it back.

Data Analysis Python

df_unstacked = stacked.[1]()
df_stacked_again = df_unstacked.[2]()

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

Aunstack

Breset_index

Cstack

Dpivot

Attempts:

3 left

💡 Hint

Common Mistakes

Using reset_index which changes index structure but does not pivot.

Using pivot which requires specific arguments.

Reversing the order of stack and unstack.

First, unstack() converts the Series back to a DataFrame. Then stack() compresses it again.

5fill in blank

hard

Fill all three blanks to unstack the second level (level=1) of the MultiIndex and then stack only the 'year' level.

Data Analysis Python

intermediate = stacked.[1](level=[2])
final = intermediate.[3](level='year')

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

Aunstack

B1

Cstack

Dreset_index

Attempts:

3 left

💡 Hint

Common Mistakes

Using level=0 instead of level=1.

Using stack for the first blank instead of unstack.

Using reset_index or pivot inappropriately.

unstack(level=1) pivots the second index level to columns, then stack(level='year') compresses the 'year' level.