Python range example and explanation

In this article are covered several examples of range function:

  • basic use
  • range by step
  • range start and end limit
  • python range next
  • accessing range elements
  • negative numbers
  • python range decrease

Basic use of range

Basic usage of range function in Python is:

for i in range(7):
    print (i)

this is equivalent to:

for i in [0,1,2,3,4,5,6]:
    print (i)

result:

0, 1, 2, 3, 4, 5, 6,
by step
Note that if you give only 1 parameter than this is the upper limit starting from 0. So if you use -7 nothing will be produced:

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

Range with start and end

You can define the start and end of the range by giving two parameters.:

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

result:

2, 3, 4, 5, 6,

Note that upper limit should be bigger otherwise nothing will be produced.

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

Range by step

Adding third parameter will define the step of the range. So you can get all even or odd numbers. Or get all numbers from 0..100 which divide to 5:

for i in range(0, 100, 5):
    print (i, end=', ')

result:

0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95,

Python range negative numbers

If you want to work with negative numbers than you have to use negative limits:

for i in range(-10, 0, 2):
    print (i, end=', ')

result:

-10, -8, -6, -4, -2,

Python range decrease

You can work with range in decreasing order by using negative step:

for i in range(10, 0, -2):
    print (i, end=', ')

result:

10, 8, 6, 4, 2,

Working with python range, check start, stop and step

You can create and assign range to python variable:

range5 = range(5, 100, 20)
print (range5)

print(range5.step)
print(range5.start)
print(range5.stop)

result:

range(5, 100, 20)
20
5
100

Check if value is in range

You can work with range in decreasing order by using negative step:

range5 = range(5, 100, 20)
print(5 in range(10))
print(5 in range5)
print(15 in range5)

result:

True
True
False

Access range elements

Ranges can be considered in some ways as a python lazy lists and the access can be done in similar way:

range5 = range(5, 100, 20)
print(range(0,10,3)[3])
print (range5[3])

result:

9, 65

Python range next

If you want to get the next value of range object then you have to use iter and then call function next on it:

range5 = range(5, 100, 20)
it = iter(range5)
print(next(it))
print(next(it))

result:

5, 25

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