nunique() for unique counts in Pandas - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

Pandas

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

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Acount

Bunique

Cnunique

Dsum

Attempts:

3 left

💡 Hint

Common Mistakes

Using count() which counts all non-null values, not unique ones.

Using unique() which returns unique values but does not count them.

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

2fill in blank

medium

Complete the code to count unique values in each column of the DataFrame.

Pandas

unique_counts = df.[1]()

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Anunique

Bunique

Ccount

Dvalue_counts

Attempts:

3 left

💡 Hint

Common Mistakes

Using unique() which returns arrays of unique values, not counts.

Using value_counts() which works on Series, not DataFrame.

The nunique() method applied to the whole DataFrame returns unique counts per column.

3fill in blank

hard

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

Pandas

unique_ages = df['age'].[1]

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Anunique()

Bnunique

Cunique()

Dcount()

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting parentheses after nunique.

Using unique() which returns unique values, not 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.

Pandas

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

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Awords

Bword_list

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong variable name for the list.

Using the wrong comparison operator in the condition.

We loop over word_list and select words longer than 3 letters to count unique 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 for words longer than 4 letters.

Pandas

result = [1]: [2] for [3] in words if len([3]) > 4

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Aword.upper()

Blen(set(word))

Cword

Dword.lower()

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase instead of uppercase for keys.

Using the wrong variable name in the loop.

The dictionary comprehension uses word.upper() as keys, counts unique letters with len(set(word)), and loops over word in words.