On 10/03/2016 13:41, Ben Mezger wrote:
Hi all,
I've been studying Object Oriented Theory using Java. Theoretically, all
attributes should be private, meaning no one except the methods itself
can access the attribute;
I suggest that you read
http://dirtsimple.org/2004/12/python-is-not-java.html and
http://dirtsimple.org/2004/12/java-is-not-python-either.html
public class Foo {
private int bar;
...
Normally in Java, we would write getters and setters to set/get the
attribute bar. However, in Python, we normally create a class like so;
class Foo(object):
bar = 0
...
And we usually don't write any getters/setters (though they exist in
Python, I have not seen much projects making use of it).
Python programmers in the main see getters/setters as unneeded, time
wasting boilerplate.
We can easily encapsulate (data hiding) Foo's class using the '_'
(underscore) when creating a new attribute, however, this would require
all attributes to have a underscore.
No, this is merely a convention that can be worked around if you really
want to. The same applies to the use of the double underscore.
According to this answer [1], it's acceptable to to expose your
attribute directly (Foo.bar = 0), so I wonder where the encapsulation
happens in Python? If I can access the attribute whenever I want (with
the except of using a underscore), what's the best way to encapsulate a
class in Python? Why aren't most of the projects not using
getters/setters and instead they access the variable directly?
You have misunderstood. The '_' is just a convention that says, "this
is private, please keep your mitts off". There is nothing to stop a
programmer from using it.
Regards,
Ben Mezger
[1] - http://stackoverflow.com/q/4555932
I suggest that you reread the stackoverflow link that you've quoted, and
take great notice of the response from Lennart Regebro, even if it has
been downvoted.
--
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.
Mark Lawrence
--
https://mail.python.org/mailman/listinfo/python-list
