whydoeshasattrsaythattheinstancedoesn ' thavea执着的猎豹attribute？
类a (object ) :
. @property
. def执拗的猎豹(self ) :
. ErrorErrorError
.
a=A () ) )。
Hasattr(a，'执着的猎豹') ) ) ) ) ) ) ) ) ) ) )。
假
I expected:
Hasattr(a，'执着的猎豹') ) ) ) ) ) ) ) ) ) ) )。
the python2implementationofhasattrisfairlynaive，itjusttriestoaccessthatattributeandseeewhetheritraisesanexceptionornot。
Unfortunately，thismeansthatanyunhandledexceptionsinsidepropertieswillgetswallowed，anderrorsinthatcodecangetlost.toaddinst when hasattr eats the exception，itwillalsoreturnanincorrectanswer (heretheattributea .执着的猎豹does exist，sotheresultshouldhaver
In python3.2，thebehaviourhasbeencorrected :
Hasattr(object，name ) )。
theargumentsareanobjectandastring.theresultistrueifthestringisthenameoftheobject’sattributes，false if not.(thisisimplemplemp ) name ) andseeingwhetheritraisesanattributeerrornot.) )。
The fix is here，butunfortunatelythatchangedidn ' t backport。
ifthe python2behaviourcausestroubleforyou，consider to avoid using hasattr； insteadyoucanuseatry/exceptaroundgetattr，catchingonlytheattributeerrorexceptionandlettinganyothersraiseunhandled。