range() in Python – Explained with Examples

The range() function in Python is used to generate a sequence of numbers. It's commonly used in loops and list comprehensions.

Basic Syntax:

range(start, stop, step)

• start (optional): Starting number of the sequence (default is 0)
• stop (required): Generate numbers up to, but not including, this number
• step (optional): Difference between each number in the sequence (default is 1)

Examples

1. Using range(stop)

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

Output:

0
1
2
3
4

• Starts from 0
• Stops at 5 (exclusive)
• Step is 1 (default)

2. Using range(start, stop)

for i in range(2, 6):
    print(i)

Output:

2
3
4
5

3. Using range(start, stop, step)

for i in range(1, 10, 2):
    print(i)

Output:

1
3
5
7
9

• Starts at 1
• Ends before 10
• Increments by 2

4. Reverse Range

for i in range(10, 0, -1):
    print(i)

Output:

10
9
8
...
1

• Generates numbers in reverse using a negative step

5. Convert range to List or Tuple

print(list(range(5)))     # [0, 1, 2, 3, 4]
print(tuple(range(3, 7))) # (3, 4, 5, 6)

6. Empty Range

print(list(range(5, 2)))  # []

• Since 5 is greater than 2 and no step is provided, it results in an empty sequence.

Use Cases

• Loops: Commonly used in for loops
• Indexing: Iterating over list indices
• List comprehension: Efficient sequence creation

Summary Table