The for loop

Learn to iterate over iterables with for.

A for loop repeats a block for each item of a collection (list, string, range):

for letter in "abc":
    print(letter)

This prints 'a', 'b', 'c' on separate lines. The in keyword specifies the collection. The loop variable (letter) takes each item in turn.

The for loop ends when the collection is exhausted. This structure is the basic tool for repetitive tasks.

Looping over strings and lists

The for loop works on ordered collections like strings and lists. Each character of a string, each item of a list is a step:

for item in [10, 20, 30]:
    print(item)

for char in "Hello":
    print(char)

You choose the loop variable name (item, char); a meaningful name makes code readable.

Assign numbers = [10, 20, 30]. Write for n in numbers: print(n).

Show example solution

numbers = [10, 20, 30]
for n in numbers:
    print(n)

Complete the for loop

for letter ____ "abc":
    print(letter)

Show answer

for letter in "abc":
    print(letter)

Next lesson: range