[Tutor] How to call a method with a print statement?

[Dave Angel]

Kent Johnson wrote:
> On Thu, Nov 12, 2009 at 6:35 AM, Luke Paireepinart
> <rabidpoobear at gmail.com> wrote:
>   
>> On Thu, Nov 12, 2009 at 5:29 AM, Jeff R. Allen <jra at nella.org> wrote:
>>     
>>> You are looking for the __str__ method. See
>>> http://docs.python.org/reference/datamodel.html#object.__str__
>>>
>>>       
>> Can't you also implement __repr__?
>>     
>
> Yes, in fact if you are only going to implement one of __str__ and
> __repr__, arguably __repr__ is a better choice. __repr__() is called
> by the interactive interpreter when it displays an object. __str__ is
> called by print, and if you don't define __str__ it will call
> __repr__. So defining only __str__ will not give a custom
> representation unless you print:
>
> In [1]: class Foo():
>    ...:     def __str__(self):
>    ...:         return "I'm a Foo"
>
> In [2]: f = Foo()
>
> In [3]: f
> Out[3]: <__main__.Foo instance at 0x1433468>
>
> In [4]: print f
> I'm a Foo
>
>
> Defining __repr__ will give the custom representation when you just
> give the name of the object:
>
> In [5]: class Foo2():
>    ...:     def __repr__(self):
>    ...:         return "I'm a Foo2"
>    ...:
>    ...:
>
> In [6]: f2=Foo2()
>
> In [7]: f2
> Out[7]: I'm a Foo2
>
> In [8]: print f2
> I'm a Foo2
>
> Kent
>
>   
And one other important place that uses __repr__() is the printing of 
containers.  So if you have a list of Foo2 objects, and you want to just say
    print mylist

it's better to have __repr__().