Stepping backwards in for loop?

[Alex Martelli]

"Gustaf Liljegren" <gustafl at algonet.se> wrote in message
news:Xns9083A46CB3B93gustaflalgonetse at 194.213.69.152...
> Can't figure out how to step backwards, character by character in a
string.
> I was looking for a loop countruct with a counter to handle this, but the
> for loop in Python doesn't let me step backwards. What is the alternative?

You have several alternatives, such as:

thestr = 'ciao'

for x in range(len(thestr), 0, -1):
    print thestr[x-1],
print

for x in range(len(thestr)):
    print thestr[-x-1],
print

aulist = list(thestr)
aulist.reverse()
for c in aulist:
    print c,
print

class Reverse:
    def __init__(self, seq):
        self.seq = seq
    def __getitem__(self, index):
        return self.seq[-index-1]
for c in Reverse('ciao'):
    print c,
print


Each of these snippets will print 'o a i c'.


Alex