[Tutor] Object references in Python

[Mats Wichmann]

On 7/16/19 2:33 PM, Steven D'Aprano wrote:

> x = Parrot()
> 
> Now x is a reference to a Parrot instance. y remains a reference to the 
> list.
> 
> x.colour is a reference to the string "blue" (by default).
> 
> x.speak is a reference to the "speak" method of Parrot objects.
> 
> 
> 
> Does this help?
> 
> 
> 

Let's add one more little cute one for good measure:

>>> def foo():
...     print("This function does Foo")
...
>>> foo()
This function does Foo
>>> # we created a function object, and foo is a reference to it
...
>>> x = foo
>>> # x should be a reference to the same object
...
>>> x()
This function does Foo
>>> x is foo
True
>>> def foo():
...     print("This function no longer Foos")
...
>>> # we created a new function object, and foo is now a reference to it
...
>>> foo()
This function no longer Foos
>>> x()
This function does Foo
>>> # x is still a reference to the original function object
...
>>> x is foo
False
>>>