"Dick Moores" <[EMAIL PROTECTED]> wrote
> Well, if deleting from the same list I'm traversing is the problem,
> why doesn't inserting the line
> lstB = lstA
>
> and deleting from lstB clear it up? The output is exactly the same.
You are not copying the list you are just making a second name
refer to the same list. You need to make a new copy, as in:
lstB = lstA[:] # a full slice creates a copy
But thats not an efficient approach if you have a big list, the
best route is to build a new list, preferably using a list
comprehension.
> I thank you for showing me another way to get the result I want, but
> first I want to know why my code didn't work.
The reason is as stated. Your solution didn't do what you thought it
did :-)
The other way you can do it is to use a while loop:
n = 0
while n < len(myList): #computed each time
if some_test(myList[n]):
del(myList[n])
else:
n += 1
Note we do not increment n when we delete an element.
I cover this in the branching topic of my tutorial in the section
Modifying collections from inside loops
HTH,
--
Alan Gauld
Author of the Learn to Program web site
http://www.freenetpages.co.uk/hp/alan.gauld
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