Conditional expressions (again)

Steven D. Majewski sdm7g at Virginia.EDU
Fri Oct 26 17:46:38 CEST 2001


On Fri, 26 Oct 2001 gbreed at cix.compulink.co.uk wrote:

> Compare
> 
> order.append(
>     spam if customer == michae1 else
>     eggs if customer == john else
>     cheese)
> 
> with
> 
> if customer == michael:
>     side0rder = spam
> elif customer == john:
>     sideOrder = eggs
> else:
>     sideOrder = cheese
> order.append(sideOrder)
> 
> in terms of how likely each error is to arise in testing, and how much 
> time it would take to work out what was going wrong.  I find that almost 
> convincing ;-)
> 

How about something like:

>>> custorders = { 'michael' : 'spam', 'john' : 'eggs' }
>>> default = 'cheese' 


>>> order.append( custorders.get( customer, default ) )


In general, table driven code is often the most clear and clean
representation, and mappings can often be a good replacement 
for conditionals. 

-- Steve 





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