I know there are better ways to print things backwards. But for some reason I can't get this to work. Any ideas why?
fruit = 'banana'
index = 0
while index < len(fruit):
print fruit[-(index)]
index = index + 1
1 Answer
You reversed everything but the b, because you started at 0, and -0 is still 0.
You end up with the indices 0, -1, -2, -3, -4, -5, and thus print b, then only anana in reverse. But anana is a palindrome, so you cannot tell what happened! Had you picked another word it would have been clearer:
>>> fruit = 'apple'
>>> index = 0
>>> while index < len(fruit):
... print fruit[-index]
... index = index + 1
...
a
e
l
p
p
Note the a at the start, then pple correctly reversed.
Move the index = index + 1 up a line:
index = 0
while index < len(fruit):
index = index + 1
print fruit[-index]
Now you use the indices -1, -2, -3, -4, -5 and -6 instead:
>>> fruit = 'banana'
>>> index = 0
>>> while index < len(fruit):
... index = index + 1
... print fruit[-index]
...
a
n
a
n
a
b
>>> fruit = 'apple'
>>> index = 0
>>> while index < len(fruit):
... index = index + 1
... print fruit[-index]
...
e
l
p
p
a
I removed the (..) in the expression -(index) as it is redundant.
answered Sep 27, 2014 at 20:38
Martijn Pieters
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1 Comment
Roger Fan
One of those weird situations where the only reason it's hard to debug is the particular example used. Not many words are a letter followed by an palindrome.
()aroundindexare redundant, and add clutter to the code.