Overview
Python Sets are specialized data structures that store unordered collections of unique elements. Unlike lists or tuples, sets automatically eliminate duplicate items and do not maintain any specific order. They are ideal for scenarios where uniqueness is essential and for performing mathematical set operations such as union, intersection, and difference.
Importance of Sets in Python
Sets play a crucial role in data management by:
- Eliminating Duplicates: Automatically ensuring all elements are unique.
- Efficient Operations: Facilitating quick computation of set operations like union and intersection.
- Optimized Performance: Providing faster membership tests compared to lists.
Using sets can simplify your code and enhance performance, especially when dealing with large datasets or requiring unique entries.
Step-by-Step Guide to Using Sets
Creating a Set
You can create a set by placing comma-separated values within curly braces {} or by using the set() constructor.
# Creating a set of unique Filipino provinces
provinces = {"Cebu", "Luzon", "Visayas", "Mindanao"}
print(provinces) # Output may vary in order
# Using the set constructor
desserts = set(["Bibingka", "Turon", "Halo-Halo"])
print(desserts)Adding and Removing Elements
- Adding Elements: Use add() to insert a single item or update() to add multiple items.
provinces = {"Cebu", "Luzon", "Visayas", "Mindanao"}
print(provinces)
# Adding a new province
provinces.add("Palawan")
print (provinces)
# Adding multiple desserts
desserts = set(["Bibingka", "Turon", "Halo-Halo"])
print(desserts)
desserts.update(["Ube Ice Cream", "Leche Flan"])
print(desserts)- Removing Elements: Use remove() to delete a specific item or discard() which does not raise an error it the item doesn’t exist.
provinces = {"Cebu", "Luzon", "Visayas", "Mindanao"}
print(provinces)
# Removingg a province
provinces.remove("Luzon")
print(provinces)
desserts = set(["Bibingka", "Turon", "Halo-Halo"])
print(desserts)
# Discarding a dessert
desserts.discard("Leche Flan")
print(desserts)Performing Set Operations
- Union: Combines elements from both sets.
provinces = {"Cebu", "Luzon", "Visayas", "Mindanao"}
print(provinces)
northern_provinces = {"Ilocos", "Benguet"}
all_provinces = provinces.union(northern_provinces)
print(all_provinces)- Intersection: Retrieves common elements between sets
provinces = {"Cebu", "Luzon", "Visayas", "Mindanao"}
print(provinces)
common = provinces.intersection(northern_provinces)
print(common) # Output: set()- Difference: Elements present in one set but not in the other.
provinces = {"Cebu", "Luzon", "Visayas", "Mindanao"}
print(provinces)
exclusive = provinces.difference(northern_provinces)
print(exclusive)- Symmetric Difference: Elements in either set but not in both.
provinces = {"Cebu", "Luzon", "Visayas", "Mindanao"}
print(provinces)
sym_diff = provinces.symmetric_difference(northern_provinces)
print(sym_diff)Example: Managing Festival Vendors
You are organizing two popular Filipino festivals: Sinulog and Ati-Atihan. Each festival has its own set of vendors selling traditional foods and crafts. Some vendors participate in both festivals, while others are exclusive to one. Using Python sets, you can efficiently manage these vendors, ensuring each vendor is listed only once and understanding their participation across the festivals.
# Vendors for Sinulog Festival
sinulog_vendors = {"Bibingka House", "Halo-Halo Hub", "Lechon King", "Ube Ice Cream"}
# Vendors for Ati-Atihan Festival
ati_atihan_vendors = {"Lechon King", "Bibingka House", "Balut Bites", "Kalamay Corner"}
# Combine all vendors into one set
all_unique_vendors = sinulog_vendors.union(ati_atihan_vendors)
print("All Unique Vendors:", all_unique_vendors)
# Find common vendors
common_vendors = sinulog_vendors.intersection(ati_atihan_vendors)
print("Common Vendors:", common_vendors)
# Find exclusive vendors in Sinulog
exclusive_sinulog = sinulog_vendors - ati_atihan_vendors
print("Exclusive to Sinulog:", exclusive_sinulog)
# Find exclusive vendors in Ati-Atihan
exclusive_ati_atihan = ati_atihan_vendors - sinulog_vendors
print("Exclusive to Ati-Atihan:", exclusive_ati_atihan)