Loop with decrement order in Python, Ruby, PHP.

Loop in decrease mode

Python

In Python, decrement is not clearly supported by syntax. By default, the loop is used to iterate over the sequence: a list, a tuple, a dictionary, a set, or a string.

For <variable> in range(start index, stop index, step) 

1. Variable: A variable is a value that starts from the start index and ends at the stop index in for loop.
2. Start index: It is an optional value. If not passed, it starts from 0. It is the integer value from which the for loop value gets starts iterating.
3. Stop index: It is the integer value from which the for loop value gets stops iterating. Step: It is the optional value. If not passed it increment the value by 1. It is an integer value that defines the increment and decrement of the loop.

1. Using Start, Stop Index, and step to Decrement for loop in Python

#Start index and stop index value
startindex = 10
stopindex = 0
step = -1
 
#applying for loop
for i in range(startindex, stopindex, step):
    print(i)

2. Using reversed() Function to Decrement for loop in Python

Reversed() function is used to loop over a sequence in reverse order

#applying reversed() function 
for i in reversed(range(5)):
    print('Output : ',i)

3. Using while

This way look isn’t an elegant way, but while was introduction is an infinite loop. So everything is hard to approach you can start to think about using while

#applying while and -= operation
s = 10
while s>0:
    print("Output : ",s)
    s -= 1

Ruby

First way:

for i in (10).downto(0)
  puts i
end

Second way:

(10).downto(0) do |i|
  puts i
end

Third way:

i=10;
until i<0
  puts i
  i-=1
end

Four way:

i = 10
while i > 0
  i -= 1
end

PHP

Elegant way:

for($i=10,$j=1;$i>=1;$i--)
{
    echo $i.'<br>';
    echo $j.'<br>';
    $j++;
}