In <mailman.793.1366317327.3114.python-l...@python.org> "Robrecht W.
Uyttenhove" <ruyttenh...@gmail.com> writes:
> I tried out the following code:
> y=[range(0,7),range(7,14),range(14,21),range(21,28),range(28,35)]
> >>> y
> [[0, 1, 2, 3, 4, 5, 6],
> [7, 8, 9, 10, 11, 12, 13],
> [14, 15, 16, 17, 18, 19, 20],
> [21, 22, 23, 24, 25, 26, 27],
> [28, 29, 30, 31, 32, 33, 34]]
> >>> y[1:5:2][::3]
> [[7, 8, 9, 10, 11, 12, 13]]
> I expected the 2D list:
> [[ 7, 10, 13],
> [21, 24, 27]]
> Any ideas?
y is just a list. It happens to be a list of lists, but that doesn't make
it a "2D" list. It's an important distinction.
y[1:5:2] is the contents of y, starting at the second element and selecting
every second element after that:
[[7, 8, 9, 10, 11, 12, 13], [21, 22, 23, 24, 25, 26, 27]]
y[1:5:2][::3] is the contents of y[1:5:2], starting at the first element and
selecting every third element after that (and there are only two elements,
so it stops after the first one):
[[7, 8, 9, 10, 11, 12, 13]]
Why were you expecting the other result?
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