when to use intern()

[Michael Hudson]

Gregory Trubetskoy <grisha at ispol.com> writes:

> It says in the manual that some things in Python get interned
> automatically. I'm not sure where intern() is necessary - 

Almost never.
 
> if I have a statement like:
> 
> if self.config.has_key("PythonOption"):
>    ...
> 
> that gets executed a lot - should I consider interning "PythonOption" or

Well, you can, but...

> is it done automatically?

Yes.

> 
> what about
> 
> PYTHON_OPTION = "PythonOption"
> if self.config.has_key(PYTHON_OPTION):
>    ...
> 
> is this interned?

Yes.

See Python/compile.c in the source distribution round about line 240
for the gory details...

HTH,
Michael

-- 
48. The best book on programming for the layman is "Alice in
    Wonderland";  but  that's because it's  the best book on 
    anything for the layman.
     -- Alan Perlis, http://www.cs.yale.edu/~perlis-alan/quotes.html