what's the best way to call a method of object without a guarantee of its existence

[Marco Mariani]

Leon wrote:

> One way,  define the object before it is used,
> like this:
> object = None

This is a good practice anyway. Conditional existance of objects is 
quite evil. Resorting to if defined('foo') is double-plus-ugly.


> The other way, using try ... catch
> try:
>      object.method()
> catch NameError:
>      pass

Except you should trap AttributeError because you defined the thing as 
None before. NameErrors should be fixed as bugs, not trapped (IMHO -- 
but in python there is always a use case for everything).

Keep in mind that AttributeError might come from inside the method(), 
which could be confusing

By using the

if stuff:
    stuff.run()

idiom, you avoid the last issue and keep it simple enough.


> for  big programs, which is better, or any other way?

Define "big", as in scope, LOCs, or number of committers?