Memory savings with categoricals in Pandas - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to convert the 'color' column to a categorical type.

Pandas

df['color'] = df['color'].[1]()

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Aastype('category')

Bto_numeric()

Cstr()

Dcopy()

Attempts:

3 left

💡 Hint

Common Mistakes

Using to_numeric() which converts to numbers, not categories.

Using str() which converts to strings, not categories.

Using astype('category') converts the column to a categorical type, which saves memory.

2fill in blank

medium

Complete the code to check the memory usage of the DataFrame.

Pandas

memory_before = df.memory_usage([1]=True).sum()

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Adetailed

Bshallow

Cdeep

Dverbose

Attempts:

3 left

💡 Hint

Common Mistakes

Using shallow which is not a valid parameter.

Using verbose which is for printing info, not memory calculation.

The deep=True option gives a more accurate memory usage including object data.

3fill in blank

hard

Fix the error in the code to convert the 'city' column to categorical.

Pandas

df['city'] = df['city'].[1]('category')

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Aconvert

Bastype

Cto_type

Dchange_type

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent methods like convert() or to_type().

The correct method to cast a pandas column type is astype().

4fill in blank

hard

Complete the code to calculate the memory usage after the conversions.

Pandas

memory_after = df.[1]([2]=True).[3]()

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Amemory_usage

Bdeep

Csum

Dinfo

Attempts:

3 left

💡 Hint

Common Mistakes

Using info() which shows summary info, not memory.

Forgetting to call sum() on the Series.

Use df.memory_usage(deep=True).sum() to get the total memory usage after converting columns to categorical.

5fill in blank

hard

Fill the blanks to compute the percentage of memory saved.

Pandas

savings_pct = round( ([1] - memory_after) / [1] * [2], [3] )

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Amemory_before

B100

C2

Dmemory_after

Attempts:

3 left

💡 Hint

Common Mistakes

Using memory_after instead of memory_before in the denominator.

Forgetting to multiply by 100 for percentage.

Wrong number of decimals in round().

The formula is round( (memory_before - memory_after) / memory_before * 100, 2 ) to get percentage saved rounded to 2 decimals.