style question - hasattr

[Terry Reedy]

"ian" <ian.team.python at saltmob.com> wrote in message 
news:a59f2b47-d1c2-4db5-82a6-34746af5d1dc at w8g2000prd.googlegroups.com...
| In old python code i would use 'has_key' to determine if an element
| was present in a dictionary.
|
| Python 3.0 will even removed 'has_key'. The reason for removal is that
| using the 'in' operator is a cleaner syntax and having two ways to
| achieve the same result is against the principle of the language.
|
| Ok, so what about 'hasattr'  ??
|    hasattr(myObject,'property')
| seems equivalent to
|    'property' in dir(myObject)
|
| I would suggest that using the 'in' is cleaner in this case also. Is
| there a performance penalty here?

Yes, the construction of the dir.
And I think there may be slight differences between the two.

tjr