How to Use Range Function in Python: Syntax and Examples

The range() function in Python generates a sequence of numbers, commonly used in loops. You can call it with one, two, or three arguments: range(stop), range(start, stop), or range(start, stop, step) to control the sequence start, end, and step size.

Syntax

The range() function can be used in three ways:

• range(stop): Generates numbers from 0 up to but not including stop.
• range(start, stop): Generates numbers from start up to but not including stop.
• range(start, stop, step): Generates numbers from start up to but not including stop, incrementing by step.

All arguments must be integers. The step can be negative to count backwards.

python

range(stop)
range(start, stop)
range(start, stop, step)

Example

This example shows how to use range() in a for loop to print numbers from 0 to 4, then from 2 to 5, and finally counting backwards from 5 to 1.

python

for i in range(5):
    print(i, end=' ')
print()

for i in range(2, 6):
    print(i, end=' ')
print()

for i in range(5, 0, -1):
    print(i, end=' ')
print()

Output

0 1 2 3 4 
2 3 4 5 
5 4 3 2 1 

Common Pitfalls

Common mistakes include:

• Using a non-integer argument causes an error.
• Forgetting that stop is exclusive, so the last number is not included.
• Using a step of zero, which raises an error.
• Confusing the order of start and stop when counting backwards.

python

try:
    list(range(1.5, 5))  # Wrong: float arguments
except TypeError as e:
    print(f"Error: {e}")

# Correct usage
print(list(range(1, 5)))

Output

Error: 'float' object cannot be interpreted as an integer
[1, 2, 3, 4]

Quick Reference

Usage	Description	Example
range(stop)	Numbers from 0 up to stop (exclusive)	range(5) → 0,1,2,3,4
range(start, stop)	Numbers from start up to stop (exclusive)	range(2, 6) → 2,3,4,5
range(start, stop, step)	Numbers from start to stop by step	range(5, 0, -1) → 5,4,3,2,1

Key Takeaways

Use range() to generate sequences of integers for loops and iterations.

The stop value is exclusive; the sequence stops before it reaches stop.

You can specify start, stop, and step to control the sequence.

Step cannot be zero and must be an integer.

range() arguments must be integers; floats cause errors.