How to loop backwards in python? [duplicate] How to loop backwards in python? [duplicate] python python

How to loop backwards in python? [duplicate]


python iteration range

range() and xrange() take a third parameter that specifies a step. So you can do the following.

range(10, 0, -1)

Which gives

[10, 9, 8, 7, 6, 5, 4, 3, 2, 1]

But for iteration, you should really be using xrange instead. So,

xrange(10, 0, -1)

Note for Python 3 users: There are no separate range and xrange functions in Python 3, there is just range, which follows the design of Python 2's xrange.

python iteration range 

for x in reversed(whatever):    do_something()

This works on basically everything that has a defined order, including xrange objects and lists.

python iteration range

All of these three solutions give the same results if the input is a string:

1.

def reverse(text):    result = ""    for i in range(len(text),0,-1):        result += text[i-1]    return (result)

2.

text[::-1]

3.

"".join(reversed(text))

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