Dynamic Dictionary Creation

[Bob van der Poel]

Skip Montanaro wrote:
> 
> Instead of
> 
>     def getNoteLen(x):
>        global TicksQ
>        ntb = { '1': TicksQ * 4,
>           '2': TicksQ * 2,
>           '4': TicksQ,
>           '8': TicksQ
>        }
>        return ntb[str(x)]
> 
> try this:
> 
>     ntb = { '1': TicksQ * 4,
>        '2': TicksQ * 2,
>        '4': TicksQ,
>        '8': TicksQ
>     }
>     def getNoteLen(x):
>        return ntb[str(x)]
> 
> or if you want the avoid the global lookup of ntb:
> 
>     def getNoteLen(x,ntb=ntb):
>        return ntb[str(x)]
> 
> It will get done once, then not repeated.  When the function is called it
> will always be a local.
> 
> Also, note that you don't need to use a global statement to read global
> variables, only to modify them.

Thanks, Skip, for the suggestion. Guess I should have been a bit more
clear, but
the reason for sticking the table inside the function was to hide the
table name. Not a big deal to define it 'globally'.

Is there a reason for the ntb=ntb in your function declaration? If the
table is external to the function, would:

	def getNoteLen(x):
		return ntb[str(x)]

be the same?

Also, to another poster whose message I lost (sorry), the reason for the
table is that there is not a 1 to 1 relationship which can be simple to
calculate. As mentioned in the original post, the example is
abbreviated.

Guess another solution would be to have this all wrapped in a class.

-- 
Bob van der Poel ** Wynndel, British Columbia, CANADA **
EMAIL: bvdpoel at kootenay.com
WWW:   http://www.kootenay.com/~bvdpoel