Subset Relationships in Python

CS 5001/5002 - Strings, Sequences & Sets

Code

#!/usr/bin/env python3
"""
Filename: subset_relationships.py
Description: Subset Relationships in Python
CS 5001/5002 - Strings, Sequences & Sets

This script demonstrates how to test subset relationships in Python using
built-in methods and operators.
"""

def main():
    # Define our sets
    S = {1, 2, 3}
    A = {2}
    B = {1, 2}
    C = {1, 2, 3}

    print(f"S = {S}")
    print(f"A = {A}")
    print(f"B = {B}")
    print(f"C = {C}")

    # Test subset relationships
    print(f"A subset S: {A.issubset(S)}")  # True
    print(f"B subset S: {B.issubset(S)}")  # True
    print(f"C subset S: {C.issubset(S)}")  # True

    # Proper vs improper subsets
    print(f"A proper subset S: {A < S}")   # True (proper subset)
    print(f"C proper subset S: {C < S}")   # False (equal sets)
    print(f"C = S: {C == S}")           # True (same set)

    # Every set is a subset of itself
    print(f"S subset S: {S.issubset(S)}")   # True

    # Empty set is subset of every set
    empty = set()
    print(f"empty subset S: {empty.issubset(S)}")  # True
    print(f"empty subset A: {empty.issubset(A)}")  # True

if __name__ == "__main__":
    main()

How to Use

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

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