Visit every value.
Let a loop do the work.

Lists and tuples are visited in order, sets without relying on order, and dictionaries through keys, values, or key-value pairs.

01 Learn02 Try03 Predict

01 Learn

A for loop can visit each value in a collection.

Lists and tuples are visited in order, sets without relying on order, and dictionaries through keys, values, or key-value pairs.

names = ["Ana", "Marko"]
for name in names:
    print(name)

Each turn through the loop assigns the next collection value to name.

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

student = {
    "name": "Ana",
    "course": "Python",
    "city": "Novi Sad"
}

for key, value in student.items():
    print(key, ":", value)

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

Lists and tuples

for value in ("red", "blue"):
    print(value)

A loop visits list and tuple items one at a time in their order.

Sets do not promise an order

for tag in {"python", "django"}:
    print(tag)

A set can be iterated, but its items do not have reliable positions or a fixed display order.

Dictionary keys, values, and pairs

for key in student:
    print(key)

for value in student.values():
    print(value)

Iterating over a dictionary gives keys. Use values() for values and items() to unpack each key and value together.

02 Try

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03 Predict

What will this program print?

Read each operation before choosing an answer.

numbers = [2, 4, 6]
total = 0

for number in numbers:
    total += number

print(total)
print(len(numbers))

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04 Understanding Check

What will this program print, and why? Explain .items(), key-value unpacking, and the total.

scores = {"Ana": 8, "Marko": 6, "Jelena": 10}
total = 0

for name, score in scores.items():
    total += score

print(total)
print(len(scores))