python range step backwards code example

Example 1: reverse index in for loop python

my_list = [1, 2, 3]
my_list.reverse()           # my_list is modified
print(my_list)              # '[3, 2, 1]'
my_revert = my_list[::-1]   # my_list stays [3, 2, 1]
print(my_revert)            # '[1, 2, 3]'
# Item by item reverse with range(<start>, <end>, <step>)
for i in range(len(my_list), 0, -1):		# my_list is [3, 2, 1]
    print(my_list[i-1])		# '1' '2' '3'
for i in reversed(range(len(my_list))):
    print(my_list[i])       # '1' '2' '3'

Example 2: python range reverse

When you call range() with three arguments, you can choose not only 
where the series of numbers will start and stop but also how big the 
difference will be between one number and the next.

range(start, stop, step)

If your 'step' is negative and 'start' is bigger than 'stop', then 
you move through a series of decreasing numbers.

for i in range(10,0,-1):
    print(i, end=' ')
# Output: 10 9 8 7 6 5 4 3 2 1

Example 3: python range backward

range(100,-1,-1)