Worthwhile to reverse a dictionary

[Kent Johnson]

rudysanford at hotmail.com wrote:
> What is the difference between
> 
>  " d1 = {'A' : '1', 'B' : '2', 'C' : '3'} "
> 
> and
> 
> " d1 = dict(A = 1, B = 2, C = 3) "  ?
> 
> All of the dictionary examples I saw (python.org, aspn.activestate.com,
> Learning Python by Lutz, among others) use d={'x' : 'y'}.
> 

The second form is only available in Python 2.3 and newer, so any example that is older 
than that will use the first form.

Kent