range() Function

range() Function

In Python, the range() function is a versatile tool that plays a crucial role in control flow, especially in iterable loops. It is a built-in function that generates a sequence of numbers, which can be used to iterate over with for loop, or other forms of loops and iterations.

The Basic Syntax of Range Function#

The range() function is commonly used in the following three forms:

• range(stop): This generates a sequence starting from 0 to stop - 1.
• range(start, stop): This generates a sequence starting from start to stop - 1.
• range(start, stop, step): This generates a sequence starting from start to stop - 1, with a step of the specified value.

Here is how the syntax generally looks:

1range([start], stop[, step])

Examples of Range Function#

Let’s get a better understanding of how range() function works with a few different examples.

Example 1: Range with One Argument#

When range() function is called with only one argument (the stop value), it generates a sequence of integers ranging from 0 to stop - 1.

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

Running this code would output: 0 1 2 3 4

Example 2: Range with Two Arguments#

When range() function is called with two arguments (the start and stop values), it generates a sequence of integers ranging from start to stop - 1.

1for i in range(2, 7):
2    print(i, end=' ')

Running this code would output: 2 3 4 5 6

Example 3: Range with Three Arguments#

When range() function is called with three arguments (the start, stop, and step values), it generates a sequence of integers from start, incrementing by step, until a number lower than stop is reached.

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

Running this code would output: 1 3 5 7 9

Use of Range Function in Script Control Flow#

In Python programs, the range() function is mostly used with iterable loops such as for loops to control the flow of the program. Here’s a simple example using the range function to print the square of numbers from 1 to n.

1n = 5
2for i in range(1, n+1):
3    print("The square of ", i, " is ", i*i)

This program would output:

The square of  1  is  1
The square of  2  is  4
The square of  3  is  9
The square of  4  is  16
The square of  5  is  25