On Wed, 19 May 2010 03:53:44 -0700, Javier Montoya wrote:
> Dear all,
>
> I've a list of float numbers and I would like to delete incrementally a
> set of elements in a given range of indexes, sth. like:
>
> for j in range(beginIndex, endIndex+1):
> print ("remove [%d] => val: %g" % (j, myList[j])) del myList[j]
>
> However, since I'm iterating over the same list, the indexes (range) are
> not valid any more for the new list. Does anybody has some suggestions
> on how to delete the elements properly?
Just delete the slice:
del myList[beginIndex:endIndex+1]
For small lists where you are deleting small chunks, this is the
simplest, most straight-forward way.
Alternatively, create a new list excluding the bits you would have
deleted, and assign it in place:
myList[:] = myList[:beginIndex] + myList[endIndex+1:]
Note carefully that you aren't just re-binding the name "myList", but
assigning to the slice myList[:].
Then there is the old-fashioned way: iterate over the list backwards,
deleting from the end towards the front.
for j in range(endIndex, beginIndex-1, -1):
del myList[j]
If your list is HUGE and you have very little memory, this is probably
the least worst way. It might be slow, but it will work.
Finally, we have this:
myList[beginIndex:] = myList[endIndex+1:]
--
Steven
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