python for everyday tasks

Michael Torrie torriem at gmail.com
Wed Nov 27 19:15:16 CET 2013


On 11/27/2013 11:05 AM, Pavel Volkov wrote:
> Thanks for all those references.
> There's this statement in the first article:
> 
> "Got a switch statement? The Python translation is a hash table, not a bunch 
> of if-then statments. Got a bunch of if-then's that wouldn't be a switch 
> statement in Java because strings are involved? It's still a hash table. "
> 
> I can't figure out how would you translate a switch statement into hash table 
> in general case.

The general case is an if/elif ladder.  But consider:

def func1(): pass
def func2(): pass
def func3(): pass

dispatch = { 0: func1,
             1: func2,
             2: func3,
           }

# do some calc
result = somecalc()
try:
  dispatch[result]()
except KeyError:
  # invalid result

That's what the article is talking about.



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