String immutability in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of string modification attempt

What is the output of this Python code?

Python

s = "hello"
s[0] = 'H'
print(s)

A TypeError

B Hello

C hello

D SyntaxError

💡 Hint

Remember that strings cannot be changed by assigning to an index.

Strings in Python are immutable, so trying to assign a new character to an index causes a TypeError.

❓ Predict Output

intermediate

Result of string concatenation

What is the output of this code?

Python

s = "cat"
s = s + "s"
print(s)

A cat

B cats

C TypeError

D catss

💡 Hint

Concatenation creates a new string.

Concatenating strings creates a new string; the original string is not changed but reassigned.

❓ Predict Output

advanced

Output after string replace method

What is printed by this code?

Python

s = "banana"
s.replace('a', 'o')
print(s)

A banana

B bonono

C SyntaxError

D TypeError

💡 Hint

Does the replace method change the original string?

The replace method returns a new string but does not change the original string because strings are immutable.

❓ Predict Output

advanced

Value of string after slicing and concatenation

What is the output of this code?

Python

s = "python"
s = 'J' + s[1:]
print(s)

A nohtyJ

B python

C Jython

D TypeError

💡 Hint

Slicing creates a new string; concatenation creates a new string.

The code creates a new string by concatenating 'J' with the slice s[1:], resulting in 'Jython'.

❓ Predict Output

expert

Final string value after chained operations

What is the output of this code?

Python

s = "immutable"
s1 = s.upper()
s2 = s1.replace('A', '@')
s3 = s2.lower()
print(s3)

A elb@tummi

B immutable

C IMMUT@BLE

D immut@ble

💡 Hint

Check the order of operations and what each method returns.

The final string s3 is the lowercase version of s2, which replaced 'A' with '@' in uppercase s1. 'IMMUTABLE' contains 'A', so s2 is 'IMMUT@BLE', and s3 is 'immut@ble'.