For loops

Looping with range

range(n) yields 0, 1, ..., n-1. for x in range(n) runs the body n times.

for i in range(5):
    print(i)

Looping over lists

for can iterate any sequence: lists, strings, tuples.

for fruit in ["apple", "pear", "kiwi"]:
    print(fruit)

enumerate

enumerate gives you the index alongside each value.

for i, fruit in enumerate(["apple", "pear"]):
    print(i, fruit)

Try it yourself

Run the example below. Edit it and see what changes.

for i in range(1, 4):
    print("step", i)
 

Common mistakes

• ⚠Forgetting range goes up to but not including the end value.
• ⚠Missing the colon after the for line.
• ⚠Modifying a list while iterating over it.