String Immutability and Its Implications

CS 5001/5002 - Strings, Sequences & Sets

Code

#!/usr/bin/env python3
"""
Filename: string_immutability.py
Description: String Immutability and Its Implications
CS 5001/5002 - Strings, Sequences & Sets

This script demonstrates the immutable nature of strings in Python and
compares them with other immutable sequences like tuples.
"""

def main():
    # Strings are immutable
    text = "hello"
    print(f"Original text: {text}")

    # This creates a NEW string, doesn't modify the original
    new_text = text.upper()
    print(f"After upper(): original = '{text}', new = '{new_text}'")

    # Trying to modify a string character raises an error
    try:
        text[0] = 'H'  # This will fail!
    except TypeError as e:
        print(f"Error: {e}")

    # String concatenation creates new strings
    greeting = "Hello"
    name = "World"
    message = greeting + " " + name  # Creates new string
    print(f"Concatenated: '{message}'")

    # Tuples are also immutable sequences
    weekdays = ("Mon", "Tue", "Wed", "Thu", "Fri")
    print(f"Weekdays tuple: {weekdays}")
    print(f"First weekday: {weekdays[0]}")

if __name__ == "__main__":
    main()

How to Use

1. Copy the code above
2. Save it as a .py file (e.g., string_immutability.py)
3. Run it with: python string_immutability.py

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Part of CS 5001/5002 - Strings, Sequences & Sets materials