range python reverse code example

Example 1: reverse for loop python

# 1.
for i in reversed(range(3)): # output: 	0
    print(i)				 #			1
    						 # 			2
# works with arrays as well , reversed(arr)

# 2.
# another alternative is
arr = [1,2,3]
# note: arr[start : end : step]
for i in arr[::-1]:			 # output:	0
  print(i)					 # 			1
  							 #			2

# 3.
# last alternative i don't recommened!
# note: range(start, end, step)
for i in range(len(arr) - 1, -1 , -1): 	# output: 	0
  print(i)								# 			1
  										# 			2
# read more on range() to understand even better how it works has the same rules as the arrays

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 reverse range

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 4: reversed(range

>>> type(range(3))
<class 'range'>

Example 5: printing number in decreasing order using For in range

range(5, -1, -1)
utilizar o sinal de menos na varial "fim" e "step"