nunique() for cardinality in Data Analysis Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to count unique values in the 'color' column.

Data Analysis Python

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

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

Anunique

Bcount

Csum

Dmean

Attempts:

3 left

💡 Hint

Common Mistakes

Using count() instead of nunique()

Using sum() which adds values instead of counting unique ones

The nunique() function counts the number of unique values in a column.

2fill in blank

medium

Complete the code to find the number of unique values in the 'city' column of the DataFrame.

Data Analysis Python

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

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

Acount

Bvalue_counts

Cunique

Dnunique

Attempts:

3 left

💡 Hint

Common Mistakes

Using unique() which returns an array instead of a count

Using value_counts() which returns counts of all values

The nunique() method counts unique values directly when called on a DataFrame column.

3fill in blank

hard

Fix the error in the code to correctly count unique values in the 'product' column.

Data Analysis Python

unique_products = df['product'].[1]

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

Anunique

Bnunique()

Ccount()

Dunique()

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting parentheses after nunique

Using unique() which returns unique values, not the count

The nunique() method must be called with parentheses to execute and return the count.

4fill in blank

hard

Fill both blanks to create a dictionary with words as keys and their unique letter counts as values.

Data Analysis Python

unique_letters = {word: len(set(word)) for word in [1] if len(word) [2] 3}

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

Awords

B>

C<

Dletters

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'letters' instead of 'words' as iterable

Using '<' instead of '>' in the condition

The dictionary comprehension loops over words and includes only words longer than 3 letters.

5fill in blank

hard

Fill all three blanks to create a dictionary with uppercase words as keys and their unique letter counts as values, only for words longer than 4 letters.

Data Analysis Python

result = [1]: len(set(word)) for word in words if len(word) [2] 4 and word.isalpha() and word.islower() == [3]

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

Aword.upper()

B>

CFalse

Dword.lower()

Attempts:

3 left

💡 Hint

Common Mistakes

Using word.lower() instead of word.upper() for keys

Using '<' instead of '>' for length condition

Using True instead of False for word.islower() check

The dictionary keys are uppercase words, filtered for length > 4, and only words that are not lowercase (hence word.islower() == False).