Alan McIntyre wrote:
Hi all,
I have a list of items that has contiguous repetitions of values, but
the number and location of the repetitions is not important, so I just
need to strip them out. For example, if my original list is
[0,0,1,1,1,2,2,3,3,3,2,2,2,4,4,4,5], I want to end up with [0,1,2,3,2,4,5].
Here is the way I'm doing this now:
def straightforward_collapse(myList):
collapsed = [myList[0]]
for n in myList[1:]:
if n != collapsed[-1]:
collapsed.append(n)
return collapsed
Is there an elegant way to do this, or should I just stick with the code
above?
Here's a solution that works for iterables other than lists:
py> def collapse(iterable):
... enumeration = enumerate(iterable)
... _, lastitem = enumeration.next()
... yield lastitem
... for i, item in enumeration:
... if item != lastitem:
... yield item
... lastitem = item
...
py> lst = [0,0,1,1,1,2,2,3,3,3,2,2,2,4,4,4,5]
py> list(collapse(lst))
[0, 1, 2, 3, 2, 4, 5]
Again, I'm still not sure I'd call this more elegant...
STeVe
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