String indexing (positive and negative) in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of positive and negative indexing

What is the output of this Python code?

Python

s = "hello"
print(s[1], s[-1])

A h o

B e o

C e h

D o e

💡 Hint

Remember, positive index starts at 0 from left, negative index starts at -1 from right.

s[1] is the second character 'e', s[-1] is the last character 'o'. So output is 'e o'.

❓ Predict Output

intermediate

Indexing with negative values

What will this code print?

Python

word = "python"
print(word[-3])

A h

B t

C o

D n

💡 Hint

Count backwards from the end starting at -1.

word[-1] is 'n', word[-2] is 'o', word[-3] is 'h'.

❓ Predict Output

advanced

Mixing positive and negative indexes

What is the output of this code snippet?

Python

text = "abcdef"
print(text[2], text[-4])

A c d

B d d

C d c

D c c

💡 Hint

Remember positive index 2 is third character, negative index -4 counts from right.

text[2] is 'c', text[-4] is 'c'. So output is 'c c'.

❓ Predict Output

advanced

Index error with out-of-range negative index

What error does this code raise?

Python

s = "abc"
print(s[-4])

A IndexError

B No error, prints 'a'

C TypeError

D KeyError

💡 Hint

Negative index must be within the string length.

Index -4 is out of range for string of length 3, so IndexError is raised.

🧠 Conceptual

expert

Length and indexing relationship

Given a string s of length 7, which index accesses the last character?

A s[7]

B s[-6]

C s[6]

D s[-7]

💡 Hint

Positive indexes start at 0, so last index is length minus one.

For length 7, last character is at index 6 (0-based). s[7] is out of range. s[-7] is first character.