[Tutor] Type Checking:/High-Jacking Reserved Words

[Remco Gerlich]

On Mon, Mar 05, 2001 at 11:26:19AM -0000, alan.gauld@bt.com wrote:
> > I would welcome some comments from anyone as to the
> > comparative advantages of the following
> > >     type(mystr) == types.StringType
> 
> This works best if you are checkjing for type several 
> times since the import overhead only gets called once.
> 
> > >     type(mystr) == type("") 
> 
> This is better if you only do it once since the extra 
> function call is probably faster than importing the 
> type module.

Since type has to return a Type itself, I bet it also imports the type
module itself (or the equivalent in C). It's not just a function call, it
has to decide what type 'mystr' is, and then it has to decide what type "" is.

*fiddle with profiler*

Hmm, oddly enough, the second is a lot faster, even if the import only
happens once for 500,000 iterations. So much for reasoning about efficiency
:).

I still don't like the way 'type(mystr) == type("")' looks, and I don't
think decisions like this should be made based on speed (after all, why not
use C if you want to do premature optimization...), but whatever.

-- 
Remco Gerlich