Alex Snast wrote:
Hello
I'm new to python and i can't figure out how to write a reverse for
loop in python
e.g. the python equivalent to the c++ loop
for (i = 10; i >= 0; --i)
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What are you trying to loop through?
If it's the contents of a list, you can reverse the list (in place) first:
L = [1,2,3]
L.reverse()
for item in L:
print item
Or you can create a new reversed (copy of the original) list and iterate
through it
for item in reversed(L):
print item
If it's just a sequence of numbers you want to generate:
range(3) generates a forward list [0,1,2], and
range(3,0,-1) generates a backward list [2,1,0]
so
for i in range(11,0,-1):
might be what you want.
If your list is huge, consider xrange rather than range.
And as always, you could just roll your own index manipulation:
i = 10
while i >=0:
# do whatever
i -= 1
Gary Herron
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