Should I use "if" or "try" (as a matter of speed)?

[John Machin]

Roy Smith wrote:

> Well, you've now got a failure.  I used to write Fortran on punch cards, 

which were then fed into an OCR gadget? That's an efficient approach -- 
where I was, we had to write the FORTRAN [*] on coding sheets; KPOs 
would then produce the punched cards.

[snip]

> 
> 3) In some cases, they can lead to faster code.  A classic example is 
> counting occurances of items using a dictionary:
> 
>    count = {}
>    for key in whatever:
>       try:
>          count[key] += 1
>       except KeyError:
>          count[key] = 1
> 
> compared to
> 
>    count = {}
>    for key in whatever:
>       if count.hasKey(key):

Perhaps you mean has_key [*].
Perhaps you might like to try

    if key in count:

It's believed to be faster (no attribute lookup, no function call).

[snip]

[*] 
humanandcomputerlanguagesshouldnotimhousecaseandwordseparatorsascrutchesbuttheydosogetusedtoit 
:-)