__call__

[TK]

Hi,

how can handle __call__? Can you give a sample?

Thanks

o-o

Thomas

 

[Simon Percivall]

Look at http://docs.python.org/ref/callable-types.html
.... def __call__(self):
.... print "the instance was called"
....the instance was called

Is this what you wanted?

 

[TK]

class Test(object):

... def __call__(self):
... print "the instance was called"
...


the instance was called

Is this what you wanted?

Yeah! Thanks.

 

[TK]

Look at http://docs.python.org/ref/callable-types.html



... def __call__(self):
... print "the instance was called"
...


the instance was called

Is this what you wanted?

Sorry but it does not work. Here's my code:
.... def __call__(self):
.... print 'Hi'
....<__main__.Test object at 0x3e6d0>


o-o

Thomas

 

[Mike Meyer]

Sorry but it does not work. Here's my code:

... def __call__(self):
... print 'Hi'
...
<__main__.Test object at 0x3e6d0>

Test() invokes the class, which returns an instance of the class.

Look back at what Simon did. He stored the value returned by Test() as
t, then called t with "t()". That's what __call__ is - the routine
invoked when an instance of a class is invoked as a callable object.

To change what happens when the class is invoked as a callable object,
you need to fool with metaclasses.

It might help if you told us what you really wanted to do with this
construct.

<mike

 

[tiissa]

Sorry but it does not work.

It _does_ work. It just don't do what you expect. That's different till
you know how to do it.

Let's see:

> ... def __call__(self):
> ... print 'Hi'
> ...

You first define a class whose members can be called.

> <__main__.Test object at 0x3e6d0>

Then you build an instance of these class. Fine.

If you want to call this instance you have to tell python:
.... def __init__(self):
.... print 'In init.'
.... def __call__(self):
.... print 'In call.'
....In init.
In init.
In call.

 

[TK]

It _does_ work. It just don't do what you expect.

Seems so;-).

Thanks a lot for help!!!

o-o

Thomas