When writing a Python program, we often need to perform the
same task several times.
For example, we may want to print numbers from 1 to 10, display a
multiplication table, or repeat a calculation.
Instead of writing the same statement repeatedly, Python provides
loops.
A loop allows us to execute a block of code several times.
💡 Think About It
What if we want Python to perform the same task several times?
One of the most commonly used loops in Python is the
for loop.
It is especially useful when we know how many times we want to
repeat an operation.
▶ A simple example
for i in range(5): print(i)
▶ Output
0 1 2 3 4
📌 What happened?
The for loop
takes each number produced by
range(5)
and stores it in the variable
i.
The print()
statement displays the value.
In this tutorial, we will learn the basics of the
for loop
and understand how the
range()
function helps us control the numbers used by the loop.
🚀 In this tutorial, you will learn
What a for loop is
Basic for loop syntax
How the range()
function works
The basic forms of range()
Simple programs using
for and
range()
1. What is a for Loop?
A for loop is used
to repeat a block of code for each value in a sequence.
It saves us from writing the same code again and again.
▶ Simple example
for i in range(5): print(i)
▶ Output
0 1 2 3 4
📌 What is happening?
The for loop
takes one value at a time and executes the indented
print(i)
statement. This continues until all the values have been processed.
🔎 Visual Understanding
A simple way to understand a loop is to think of it as a repeated
sequence of actions:
🔄 Get a value
→
Run the code
→
Get the next value
▶ How the loop works
i = 0 → print(0) i = 1 → print(1) i = 2 → print(2) i = 3 → print(3) i = 4 → print(4)
⭐ Beginner Tip
Don’t worry about understanding every detail of
range() yet.
We will learn how range()
works step by step in the next section.
Now that we understand the basic idea of a
for loop,
let’s see how its basic syntax is written in Python.
2. Basic Syntax of a for Loop
The basic structure of a Python for loop
is simple. It consists of a for statement
followed by the code that should be repeated.
▶ Basic syntax
for variable in range(…): statement
Let’s understand the main parts of this syntax:
Part
Meaning
for
Starts the loop
variable
Stores the current value
in
Gets values from range()
range()
Produces a sequence of numbers
statement
Code executed repeatedly
⭐ Beginner Tip
The code inside the loop must be
indented.
Indentation tells Python which statements belong to the loop.
Now that we know the basic syntax, let’s understand the
range()
function and see how it controls the values used by the loop.
3. Understanding the range() Function
The range() function
is commonly used with a for loop
to generate a sequence of numbers.
Let’s begin with the simplest form of
range().
range(stop)
When range()
has only one value, that value is the
stop value.
Python starts counting from 0.
▶ Example
for i in range(5): print(i)
▶ Output
0 1 2 3 4
⭐ Important Rule
range(5)
starts from 0
and stops before 5.
Therefore, 5 is not included.
🔎 Visual Understanding
Think of range(5)
as moving through the numbers from 0 up to, but not including, 5.
range(5)
0 1 2 3 4 5
✓ ✓ ✓ ✓ ✓ ✗
📌 Remember:
The last value,
5,
is the stop value,
so it is not included in the sequence.
💡 Quick view
range(5)
→
0, 1, 2, 3, 4
The range()
function can also start from a number other than 0.
Let’s look at the next form:
4. range(start, stop)
The second form of range()
allows us to specify both a starting value and a
stopping value.
💡 Syntax:
range(start, stop)
▶ Example
for i in range(2, 7): print(i)
▶ Output
2 3 4 5 6
▶ start
The first value in the sequence.
▶ stop
The value where the sequence stops.
So Python generates:
2, 3, 4, 5, 6
⭐ Remember
The start
value is included, but the
stop
value is excluded.
🔎 Visual Understanding
range(2, 7)
2 3 4 5 6 7
✓ ✓ ✓ ✓ ✓ ✗
📌 In this example:
Python starts at 2 and generates the numbers
up to 6. It stops before 7.
Next, let’s see how the step
value can be used to control how much the numbers change each time.
5. range(start, stop, step)
The third form of range()
lets us specify how much the value should change after each iteration.
This value is called the step.
💡 Syntax:
range(start, stop, step)
▶ Example 1
for i in range(2, 10, 2): print(i)
▶ Output
2 4 6 8
🔎 Understanding the three values
2
→ starting value
10
→ stopping value
2
→ increase by 2 each time
2 → 4 → 6 → 8
Increase by 2 each time
📌 Remember:
The start value is included, but the
stop value is excluded. The
step tells Python how much to change the value
each time.
Another Simple Example
The step does not have to be 2. For example, a step of
3 increases the
value by 3 each time.
▶ Example 2
for i in range(1, 10, 3): print(i)
▶ Output
1 4 7
⭐ Quick Understanding
range(1, 10, 3)
produces 1, 4, 7.
After each value, Python adds 3
and stops before 10.
Now that we know the three basic forms of
range(),
let’s use them to write some simple Python programs.
6. Three Forms of range()
Python provides three basic ways to use the
range() function.
Here’s a quick summary:
Form
Example
Values
range(stop)
range(5)
0, 1, 2, 3, 4
range(start, stop)
range(2, 6)
2, 3, 4, 5
range(start, stop, step)
range(2, 10, 2)
2, 4, 6, 8
⭐ Quick Reminder
In all three forms, the
stop value is excluded.
The step is used
to control how the value changes.
💡 Easy way to remember
One value
→ stop only
|
Two values
→ start, stop
|
Three values
→ start, stop, step
Now let’s put these concepts into practice with some simple
for loop programs.
7. Simple Programs Using for + range()
Now that we understand the basic forms of
range(),
let’s use them in some simple Python programs.
💡 Tip:
Try running each program yourself and observe the output.
Program 1 – Print numbers from 1 to 10
▶ Python
for i in range(1, 11): print(i)
Program 2 – Print even numbers
▶ Python
for i in range(2, 11, 2): print(i)
Program 3 – Print odd numbers
▶ Python
for i in range(1, 10, 2): print(i)
Program 4 – Print numbers from 10 to 1
Here we use a negative step to count backwards.
▶ Python
for i in range(10, 0, -1): print(i)
Program 5 – Find the sum of numbers
▶ Python
total = 0
for i in range(1, 6): total = total + i
print(“Sum =”, total)
Output:Sum = 15
Program 6 – Multiplication table
▶ Python
num = 5
for i in range(1, 11): print(num, “×”, i, “=”, num * i)
⭐ Practice Tip
Change the numbers in these programs and run them again.
This is a simple way to understand how
range()
controls the loop.
These examples cover some common beginner uses of
for loops with
range().
Next, let’s look at some common mistakes beginners may encounter.
📌 Remember This
Here are a few important points to remember when using
for loops with
range().
💡 Remember:
In
range(start, stop),
the stop
value is not included.
⭐ Beginner Tip:
When only one number is given to
range(),
Python starts counting from
0.
🔎 Remember:
In
range(start, stop, step),
the step tells Python how much the value changes
each time.
⚠ Common Mistake:
Remember to put a colon
:
at the end of the
for
statement and indent the code inside the loop.
🧠 Quick Summary
range(stop)
→ starts from 0
range(start, stop)
→ starts from start
range(start, stop, step)
→ changes by step
stop
→ always excluded
8. Practice Questions
Now it’s your turn! Try these simple exercises using
for loops and
range().
💡 Practice Tip
Try writing and running each program yourself before looking for a solution.
📝 Practice 1
Write a Python program to print numbers from
1 to 20.
📝 Practice 2
Print the even numbers from
2 to 20.
📝 Practice 3
Print the odd numbers from
1 to 19.
📝 Practice 4
Print numbers from 10 down to 1.
📝 Practice 5
Write a Python program to print the
multiplication table of 7.
⭐ Bonus Challenge
Print the numbers from 5 to 50
with a step of 5.
📚 Want to check your answers?
The solutions can be provided separately so that you can
first try the exercises on your own.
Once you are comfortable with these examples,
you are ready to explore more ways of using
for loops in Python.
9. Practice Questions – Solutions
Here are the solutions to the practice questions.
Compare your programs with these simple solutions and try to understand
how range()
is used in each example.
💡 Tip:
Don’t just compare the output. Look at the
start,
stop, and
step values.
✅ Practice 1 – Numbers from 1 to 20
▶ Solution
for i in range(1, 21): print(i)
Why 21?
The stop value is excluded, so the sequence ends at 20.
✅ Practice 2 – Even numbers from 2 to 20
▶ Solution
for i in range(2, 21, 2): print(i)
Step = 2
skips every alternate number.
✅ Practice 3 – Odd numbers from 1 to 19
▶ Solution
for i in range(1, 20, 2): print(i)
Step = 2
generates only the odd numbers.
✅ Practice 4 – Numbers from 10 down to 1
▶ Solution
for i in range(10, 0, -1): print(i)
Step = -1
makes the loop count backwards.
✅ Practice 5 – Multiplication table of 7
▶ Solution
num = 7
for i in range(1, 11): print(num * i)
Output:
7, 14, 21, 28, 35, 42, 49, 56, 63, 70
⭐ Bonus Challenge – Solution
▶ Solution
for i in range(5, 51, 5): print(i)
Output:
5, 10, 15, 20, 25, 30, 35, 40, 45, 50
🧠 Key Takeaway
The main idea is to choose the correct
start,
stop, and
step
values for range().
Remember that the stop value is excluded.
🎯 Conclusion
In this tutorial, you learned how to use Python’s
for loop with the
range() function.
You also learned its three basic forms and used them in simple programs.
⭐ Keep practicing with different values of
range()
to become comfortable with loops.
🚀 What’s next?
In the next tutorials, we’ll explore more ways to use
for loops
in Python.
Hey Engineers, welcome to the award-winning blog,Engineers Tutor.
I'm Gopal Krishna. a professional engineer & blogger from Andhra Pradesh, India.
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