how can i know if a python object have a attribute such as 'attr1'?

[Terry Reedy]

On 1/23/2010 10:56 AM, Arnaud Delobelle wrote:
> thinke365<thinke365 at gmail.com>  writes:
>
>> for example, i may define a python class:
>> class A:
>>       def sayHello():
>>            print 'hello'
>>
>> a = A()
>> a.attr1 = 'hello'
>> a.attr2 = 'bb'
>>
>> b = A()
>> a.attr2 = 'aa'
>>
>> how can i know whether an object have an attribute named attr1?
>
> hasattr(a, 'attr1')

or
try: a.attr1
except AttributeError: pass

Terry Jan Reedy