String Basics and Memory Representation in DSA Python - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the length of the string.

DSA Python

word = "hello"
length = len([1])
print(length)

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A"word"

Bword

Clen

Dhello

Attempts:

3 left

💡 Hint

Common Mistakes

Using quotes around the variable name like "word" which makes it a string literal.

Using the function name len inside len().

The len() function returns the number of characters in the string variable word.

2fill in blank

medium

Complete the code to get the first character of the string.

DSA Python

word = "world"
first_char = word[[1]]
print(first_char)

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

A-1

B1

Cword

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 as the index which gives the second character.

Using -1 which gives the last character.

String indexing starts at 0, so word[0] gives the first character.

3fill in blank

hard

Fix the error in the code to get the last character of the string.

DSA Python

word = "python"
last_char = word[[1]]
print(last_char)

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

A-len(word)

B0

Clen(word) - 1

Dlen(word)

Attempts:

3 left

💡 Hint

Common Mistakes

Using len(word) which is out of range.

Using 0 which gives the first character.

The last character is at index len(word) - 1 because indexing starts at 0.

4fill in blank

hard

Fill both blanks to create a substring from the second to the fourth character (inclusive).

DSA Python

word = "example"
substring = word[[1]:[2]]
print(substring)

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A1

B4

C5

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using end index 3 which excludes the fourth character.

Using start index 2 which skips the second character.

Substring slicing uses start index inclusive and end index exclusive. To get characters 2 to 4, use word[1:4].

5fill in blank

hard

Fill all three blanks to create a dictionary with words as keys and their lengths as values, only for words longer than 3 characters.

DSA Python

words = ["cat", "house", "dog", "elephant"]
lengths = [1]: [2] for word in words if len(word) [3] 3
print(lengths)

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A{word}

Blen(word)

C>

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Missing the opening curly brace.

Using the wrong comparison operator.

Swapping key and value positions.

The dictionary comprehension syntax is {key: value for item in list if condition}. Here, keys are words and values are their lengths. The condition filters words longer than 3 characters.