Character Frequency Counting in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to initialize an empty dictionary for counting characters.

DSA Python

freq = [1]

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

A''

B{}

Cset()

D[]

Attempts:

3 left

💡 Hint

Common Mistakes

Using a list [] instead of a dictionary.

Using a string '' which cannot store counts.

Using a set() which does not store counts.

We use an empty dictionary {} to store character counts.

2fill in blank

medium

Complete the code to loop through each character in the string 'text'.

DSA Python

for [1] in text:
    freq[char] = freq.get(char, 0) + 1

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

Achar

Bletter

Cword

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using a variable name different from the one inside the loop.

Using 'word' which implies multiple characters.

Using 'item' which is vague.

We use 'char' as the variable name to represent each character in the string.

3fill in blank

hard

Fix the error in the code to correctly update the frequency count.

DSA Python

freq[char] = freq.[1](char, 0) + 1

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

Aget

Bset

Cadd

Dappend

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'add' which is not a dictionary method.

Using 'set' which replaces the whole dictionary.

Using 'append' which is a list method.

The 'get' method returns the current count or 0 if the character is not yet in the dictionary.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that counts characters only if they appear more than once.

DSA Python

freq = {char: text.count(char) for char in [1] if text.count(char) [2] 1}

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

Aset(text)

Blist(text)

Ctext

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using list(text) which includes duplicates.

Using '<' instead of '>' causing wrong filtering.

Using dict(text) which is invalid here.

We use set(text) to avoid counting duplicates multiple times and '>' to filter characters appearing more than once.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that counts characters and includes only those with count at least 2.

DSA Python

freq = [1]: [2] for [3] in set(text) if text.count(char) >= 2

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

A{char

Btext.count(char)

Cchar

Dchar:

Attempts:

3 left

💡 Hint

Common Mistakes

Missing the opening curly brace.

Using wrong variable names.

Incorrect order of key and value.

The dictionary comprehension syntax requires curly brace start '{char', value expression 'text.count(char)', and loop variable 'char'.