for loops and range() in Python: iterate without the busywork

You already know how to count from 1 to 10 with while. A counter, a condition, an increment — four lines of code where three of them exist only to serve the fourth. That works. But Python has a better tool for situations like this:

# while: you manage the counter yourself
counter = 1
while counter <= 10:
    print(counter)
    counter += 1

# for: Python manages it for you
for i in range(1, 11):
    print(i)

Same result. Half the ceremony. The difference isn’t just aesthetic — it’s about intent. The for loop says “I know exactly what I want to iterate over.” The while says “keep going until this condition is false.” When you know the sequence upfront, for is the right tool.

What is a for loop?

A for loop iterates over a sequence of elements — one at a time, in order — and runs a block of code for each one. When it runs out of elements, it stops on its own.

fruits = ["apple", "pear", "grape"]

for fruit in fruits:
    print(fruit)  # Print each fruit

apple
pear
grape

The structure is for <variable> in <sequence>:. On each iteration, the variable (fruit) takes the value of the next element. No indexing, no incrementing — the loop handles it.

One thing that catches beginners off guard: the loop variable doesn’t disappear when the loop ends. After the for finishes, it’s still in scope, holding the value from the last iteration.

for fruit in fruits:
    print(fruit)

print(fruit)  # "grape" — still accessible after the loop

It’s not a bug — it’s just how Python scoping works for loop variables. File this away; you’ll appreciate knowing it the first time you need to debug something after a loop.

range(): generating number sequences

Iterating over an existing list is useful, but often you just want to repeat something a set number of times. That’s what range() is for — it generates a sequence of integers on demand.

It comes in three forms:

range(stop)

The simplest: generates numbers from 0 up to (but not including) stop.

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

0
1
2
3
4

Notice: range(5) gives you five numbers starting at 0. The stop value is not included — this is the same “half-open interval” convention you’ll see everywhere in Python, from slicing to indexing.

range(start, stop)

When you want to start somewhere other than zero:

for i in range(1, 6):
    print(i)  # 1, 2, 3, 4, 5

1
2
3
4
5

Clean and readable — no + 1 hacks.

range(start, stop, step)

The third argument controls the step — how much the sequence advances on each iteration.

for i in range(0, 11, 2):
    print(i)  # Even numbers from 0 to 10

0
2
4
6
8
10

A negative step lets you count backwards:

for i in range(10, 0, -1):
    print(i)  # Countdown from 10 to 1

10
9
8
7
6
5
4
3
2
1

Don’t stress about memorizing all three forms right now. You’ll use range(n) the vast majority of the time — “repeat this n times” covers most everyday cases. The rest you’ll pick up as you go.

Iterating over other sequences

for loops aren’t limited to lists and ranges. They work with anything iterable — which, for now, you can read as “anything that has elements to loop through.”

Strings are iterable — each character is its own element:

for char in "Python":
    print(char)

P
y
t
h
o
n

You’ll get a full introduction to lists in the next tutorial, but the pattern is exactly the same as you saw with the fruits example. The for loop is generic — it doesn’t care whether you’re going through characters, numbers, or anything else. The mechanism is always the same.

break: stop early

Just like with while, you can cut a for loop short with break. The moment Python hits a break, it exits the loop immediately — no remaining elements are processed.

numbers = [3, 7, 2, 9, 4, 6, 1]

for number in numbers:
    if number == 9:
        print("Found 9, stopping.")
        break   # No need to keep looking
    print(number)

3
7
2
Found 9, stopping.

Once break fires, 4, 6, and 1 never get touched. If what you’re looking for appears early in a long list, break saves you from processing the entire thing.

Here’s where it gets interesting: Python has an else clause for for loops. The else block runs only if the loop completed without hitting a break. If break fires, the else is skipped entirely:

emails = ["user@example.com", "admin@site.com", "support@company.com"]
target = "another@email.com"

for email in emails:
    if email == target:
        print("Email found.")
        break
else:
    print("Email not found in the list.")  # Only runs if no break occurred

Email not found in the list.

If you’ve used other languages and this for-else pattern feels strange — you’re not alone. It surprises most people the first time. But once it clicks, it’s genuinely useful for “search and report” scenarios where you want different behavior depending on whether the search succeeded.

Nested loops: a for inside a for

You can put a for inside another for. For every iteration of the outer loop, the inner loop runs completely through all of its iterations before the outer loop moves on.

for row in range(1, 4):
    for col in range(1, 4):
        print(f"({row},{col})", end=" ")  # Print on same line
    print()  # New line after each row

(1,1) (1,2) (1,3) 
(2,1) (2,2) (2,3) 
(3,1) (3,2) (3,3) 

The outer loop handles rows; the inner loop handles columns. A multiplication table is the classic example:

for i in range(1, 6):
    for j in range(1, 6):
        result = i * j
        print(f"{result:3}", end="")  # Right-align in 3 chars
    print()

  1  2  3  4  5
  2  4  6  8 10
  3  6  9 12 15
  4  8 12 16 20
  5 10 15 20 25

Nested loops work well for two-dimensional structures: tables, grids, coordinate pairs. One thing to keep in mind: the operations multiply. A loop of 100 inside a loop of 100 is 10,000 total operations. Add a third loop of 100 and you’re at 1,000,000. Two levels of nesting is fine; three levels is usually a sign to rethink the approach.

for vs while: the definitive breakdown

Situation	Use
You know how many times to repeat	for
You have a sequence to iterate over	for
Reading a file from start to finish	for
Iterating over a list, string, or range	for
The stopping condition depends on external input	while
Waiting for valid user input	while
A game that runs until the player loses	while
Retry loops with unpredictable timing	while

In practice, you’ll reach for for far more often than while. Most iteration in Python has a concrete sequence to go through, and for handles it more clearly and directly than managing the loop yourself.

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With for and range() in your toolkit, you can iterate over any sequence without tracking a counter. The natural next step is having something interesting to iterate over: in the next tutorial you’ll learn about lists — Python’s most versatile data structure — including how to create them, access elements by index, and combine them with everything you’ve learned so far.

Never stop coding!

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💡 Challenge: Write a program that generates and prints the multiplication tables from 1 to 10, formatted so each result takes the same amount of space (try f"{result:4}" for alignment). Bonus: ask the user to enter a number between 1 and 10 and show only that table — with the option to request another one until they decide to quit.