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How to add to a set in Python

Unveiling Sets in Python

Sets in Python are akin to a real-life mathematical set. Imagine having a box filled with different items. Each item is unique, and there's no specific order in which they're arranged. A set in Python works just like this box. It is a collection of unique items, unordered and unindexed. As we dive in, we'll learn how to add items to our Python 'box'.

Creating a Set

The first step is creating a set. To create a set, we use curly braces {} or the set() function.

# Creating a set using curly braces
fruits = {"apple", "banana", "cherry"}
print(fruits)

# Creating a set using the set() function
colors = set(["red", "green", "blue"])
print(colors)

This will output:

{'apple', 'banana', 'cherry'}
{'blue', 'red', 'green'}

Adding Items to a Set

Once we have our set, we can start adding items into it. We can add items to a set using the add() function. Let's add 'grape' to our fruits set.

fruits.add("grape")
print(fruits)

This will output:

{'apple', 'banana', 'cherry', 'grape'}

What if I want to add multiple items?

For adding multiple items, Python provides the update() function. It takes an iterable (anything where we can loop over: lists, sets, tuples) as an input. Let's add 'mango' and 'orange' to our fruits set.

fruits.update(["mango", "orange"])
print(fruits)

This will output:

{'cherry', 'apple', 'grape', 'banana', 'orange', 'mango'}

Handling Duplicates

Remember when I said sets are like a box of unique items? Here's where it comes into play. What happens when you try to add an item that's already in the set? Let's see.

fruits.add("apple")
print(fruits)

This will still output:

{'cherry', 'apple', 'grape', 'banana', 'orange', 'mango'}

Even though we tried to add 'apple' again, Python ignored it because 'apple' is already in the fruits set. That's the beauty of sets - they automatically handle duplicates for us.

The Power of Python Sets

Sets might seem simple, but they're mighty. Let's say we have another set of fruits, tropical_fruits. We can use sets to quickly find common items (using intersection) or combine all items (using union). Let's see this in action:

tropical_fruits = {"banana", "mango", "pineapple"}

# Find common fruits
common_fruits = fruits.intersection(tropical_fruits)
print(common_fruits)

# Combine all fruits
all_fruits = fruits.union(tropical_fruits)
print(all_fruits)

This will output:

{'banana', 'mango'}
{'cherry', 'pineapple', 'apple', 'grape', 'banana', 'orange', 'mango'}

Conclusion: The Set Magic Trick

Congratulations! You've just learned how to add items to a set in Python. We started by creating a set, then we added items using the add() and update() functions. We also saw how Python sets automatically handle duplicate items.

Think of using sets like performing a magic trick. You have this magical box (your set), where you can throw in objects (your items) without worrying about arranging them, and duplicate items disappear like a puff of smoke. Even better, this magic box can instantly find common objects with another box or combine all objects into a bigger box.

Just like a good magic trick, the possibilities with Python sets are endless and exciting. So, roll up your sleeves, start experimenting and create your own magic with Python sets!