On Friday 24 July 2009 11:07:30 am Inky 788 wrote:
> On Jul 23, 3:42 am, Hendrik van Rooyen <hend...@microcorp.co.za>
> > if you think it is contrived, then please consider how you would
> > keep track of say the colour of a pixel on a screen at position
> > (x,y) - this is about the simplest "natural" tuple format and
> > example.
>
> My guess is that this is probably the way most people do it:
[...]
> def make_array_of_pixels(num_columns, num_rows):
[...]
If you need to hold /every/ pixel on the screen, it makes sense to have a
bidimentional array of points and colors. But if you need to hold a
non-rectangular subset, or even a subset that doesn't need to be rectangular,
you can either use dicts, or ... do what you did. Most people will use the
less contrived version of:
screen = {}
screen[1,2] = (rand(), rand(), rand())
(btw, in your make_a_pixel function, unless you want to make the pixels
updatable in place, you should also be using a tuple).
Sparse datasets are extremely common, and dicts are a good way to
[temporarily] store them.
As someone mentioned before, dictionaries are essential to python. Don't go
out of your way to avoid them, unless you have a /reason/ to do it.
Btw,
def get_color(point):
return screen[point]
is way more readable (and less obscure) than
def get_color(point):
return rows_of_pixels[point[0]][point[1]]
Regards,
--
Luis Zarrabeitia (aka Kyrie)
Fac. de Matemática y Computación, UH.
http://profesores.matcom.uh.cu/~kyrie
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