On Apr 17, 9:47 am, Michael Hoffman <[EMAIL PROTECTED]> wrote:
> [EMAIL PROTECTED] wrote:
> > hi
> > i have a list (after reading from a file), say
> > data = [ 'a','b','c','d','a','b','e','d']
>
> > I wanted to insert a word after every 'a', and before every 'd'. so i
> > use enumerate this list:
> > for num,item in enumerate(data):
> > if "a" in item:
> > data.insert(num+1,"aword")
> > if "d" in item:
> > data.insert(num-1,"dword") #this fails
> > but the above only inserts after 'a' but not before 'd'. What am i
> > doing wrong? is there better way?thanks
>
> If you modify a list while you are iterating over it, you may get
> unexpected results (an infinite loop in this case for me). Also ("a" in
> item) will match "aword" since "a" is a component of it. I imagine you
> mean (item == "a").
>
> Try this:
>
> output = []
> for item in data:
> if item == "d":
> output.append("dword")
> output.append(item)
> if item == "a":
> output.append("aword")
>
> >>> output
> ['a', 'aword', 'b', 'c', 'dword', 'd', 'a', 'aword', 'b', 'e', 'dword', 'd']
> --
> Michael Hoffman
Infinite loop for me too! ^_^, should think of it b4 pressing F5.
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