On 11 July 2013 15:54, Russel Walker <russ.po...@gmail.com> wrote:
> ...oh and here is the class I made for it.
>
> class xslice(object):
> '''
> xslice(seq, start, stop, step) -> generator slice
> '''
>
> def __init__(self, seq, *stop):
Wouldn't it be better if it has the same signature(s) as itertools.islice?
> if len(stop) > 3:
> raise TypeError("xslice takes at most 4 arguments")
> elif len(stop) < 0:
How would len(stop) be negative?
> raise TypeError("xslice requires atleast 2 arguments")
> else:
> start, stop, step = (((0,) + stop[:2])[-2:] + # start, stop
> (stop[2:] + (1,))[:1]) # step
> stop = min(stop, len(seq))
> self._ind = iter(xrange(start, stop, step))
> self._seq = seq
>
> def __iter__(self):
> return self
>
> def next(self):
> return self._seq[self._ind.next()]
>
>
>
> Although now that I think about it, it probably should've just been a simple
> generator function.
Or you can use itertools.imap:
def xslice(sequence, start_or_stop, *args):
indices = xrange(*slice(start_or_stop, *args).indices(len(sequence)))
return imap(sequence.__getitem__, indices)
Oscar
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