I'm talking about doing something like:
for(i=n; i>=1; --i) {
//do something with i
}
I can think of some ways to do so in python (creating a list of range(1,n+1)
and reverse it, using while
and --i
, ...) but I wondered if there's a more elegant way to do it. Is there?
EDIT: Some suggested I use xrange() instead of range() since range returns a list while xrange returns an iterator. But in Python 3 (which I happen to use) range() returns an iterator and xrange doesn't exist.
def reverse(text):
reversed = ''
for i in range(len(text)-1, -1, -1):
reversed += text[i]
return reversed
print("reverse({}): {}".format("abcd", reverse("abcd")))
for x in reversed(whatever):
do_something()
This works on basically everything that has a defined order, including xrange
objects and lists.
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))
To reverse a string without using reversed
or [::-1]
, try something like:
def reverse(text):
# Container for reversed string
txet=""
# store the length of the string to be reversed
# account for indexes starting at 0
length = len(text)-1
# loop through the string in reverse and append each character
# deprecate the length index
while length>=0:
txet += "%s"%text[length]
length-=1
return txet
Source: Stackoverflow.com