Keep values unique.
Do not rely on order.

Sets remove duplicates and are useful when membership matters more than position.

01 Learn02 Try03 Predict

01 Learn

A set keeps unique values without indexes.

Sets remove duplicates and are useful when membership matters more than position.

tags = {"python", "django", "python", "ai"}
print(len(tags))

The repeated value appears only once in a set.

Try changing one value, then explain which part of the collection changed and why.

↳

Keep this in mind: Read the collection operation before predicting the result.

Try it

tags = {"python", "django", "python", "ai"}

print(len(tags))
print("django" in tags)

tags.add("data")
print("data" in tags)

Run the example, then change one value and observe the result.

02 Try

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03 Predict

What will this program print?

Read each operation before choosing an answer.

a = {1, 2, 3}
b = {3, 4, 5}

print(len(a & b))
print(len(a | b))

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04 Understanding Check

What will this program print, and why? Explain duplicates and membership.

visitors = ["Ana", "Marko", "Ana", "Jelena"]
unique_visitors = set(visitors)

print(len(visitors))
print(len(unique_visitors))
print("Ana" in unique_visitors)