hasattr() vs try-except block to deal with non-existent attributes

Question

if hasattr(obj, \'attribute\'):
    # do somthing

vs

try:
    # access obj.attribute
except AttributeError, e:
    # deal with Attr         


        

Answer 1

From a practical point of view, in most languages using a conditional will always be consderably faster than handling an exception.

If you're wanting to handle the case of an attribute not existing somewhere outside of the current function, the exception is the better way to go. An indicator that you may want to be using an exception instead of a conditional is that the conditional merely sets a flag and aborts the current operation, and something elsewhere checks this flag and takes action based on that.

That said, as Rax Olgud points out, communication with others is one important attribute of code, and what you want to say by saying "this is an exceptional situation" rather than "this is is something I expect to happen" may be more important.