Sequence-spreading

[gzeljko]

Joshua Marshall <jmarshal at mathworks.com> wrote in message
news:998ba7$5j7$1 at news.mathworks.com...
> gzeljko <gzeljko at sezampro.yu> wrote:
>
> > Alex Martelli <aleaxit at yahoo.com> wrote in message
> >> offsets = [ [] for i in range(pm) ]
> >> for i in range(len(arg)):
> >>     offsets[i%pm].append(i)
> >>
> >>
> >> Alex
> >>
>
> > Old syntax yet works:
>
> > offsets = [[]]*pm
>
> Careful here:
>
>  >>> x = [[]]*2
>  >>> y = [[] for i in range(2)]
>  >>> x
>  [[], []]
>  >>> y
>  [[], []]
>  >>> x[0] is x[1]
>  1
>  >>> y[0] is y[1]
>  0
>
> The first way gives you the same value at each element ("[]" is
> evaluated once), while the second way gives you distinct values ("[]"
> is evaluated for each element).
> --

[Careful]*3

Thanx.

ly-y'rs-gzeljko