Loops in Python (for, while)

Friendly introduction

Have you ever done something again and again, like taking 10 shots in basketball or practicing a song 5 times? A loop in Python is a way to tell the computer: "Repeat this task for me!" Loops save time and make your programs shorter and smarter.

What is a loop?

A loop repeats a block of code multiple times.

for loop: Best when you know exactly how many times to repeat or when you're going through items in a list.
while loop: Best when you want to repeat until a condition becomes false.

Step 1: The for loop

Use for when you want to loop a certain number of times or over a collection like a list or a word.

Example 1: Count from 1 to 5

for i in range(1, 6):  # 1 to 5 (6 is not included)
    print(i)

Example 2: Loop over a list

fruits = ["apple", "banana", "cherry"]
for fruit in fruits:
    print("I like", fruit)

Example 3: Loop over each letter in a word

word = "code"
for letter in word:
    print(letter)

Step 2: The while loop

A while loop runs as long as a condition is true. Make sure something inside the loop changes, or it will loop forever!

Example 1: Countdown

count = 5
while count > 0:
    print(count)
    count -= 1  # subtract 1 each time
print("Blast off!")

Example 2: Keep doubling until you reach 100

x = 1
while x < 100:
    print(x)
    x *= 2  # multiply x by 2 each time
print("Done")

Important: Avoid infinite loops!

This will never end because the condition is always True and we never change it:

# Don't do this:
# while True:
#     print("looping forever!")

If you do need a forever loop, make sure you have a way to stop it (like a break).

Step 3: Stopping or skipping in a loop (bonus)

break stops the loop immediately.
continue skips just the current turn and moves to the next one.

# break example
for n in range(1, 10):
    if n == 5:
        break
    print(n)
print("Stopped at 5")

# continue example
for n in range(1, 6):
    if n == 3:
        continue  # skip printing 3
    print(n)

Mini exercise: Your turn!

Task: Print the multiplication table of 7 from 1 to 10 (like "7 x 1 = 7" up to "7 x 10 = 70") using a for loop.

Hints:

Use range(1, 11) to get numbers 1 to 10.
Multiply 7 by the loop variable and print neatly.

Sample answer (peek if you're stuck):

for i in range(1, 11):
    print("7 x", i, "=", 7 * i)

Challenge (optional): Do the same table using a while loop.

i = 1
while i <= 10:
    print("7 x", i, "=", 7 * i)
    i += 1

Quick summary

Loops repeat code so you don't have to.
Use for to loop a set number of times or over items (range, lists, strings).
Use while to repeat until a condition becomes false—remember to update your variables!
break stops a loop; continue skips one turn.
Practice by writing loops that count, list items, or print patterns like tables.

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