Access modifiers in Python :
In C++ and Java, things are pretty straight-forward. There are 3 magical and easy to remember access modifiers, that will do the job (public, protected and private).
But there’s no such a thing in Python. That might be a little confusing at first, but it’s possible too.
Public:
All member variables and methods are public by default in Python. So when you want to make your member public, you just do nothing.
Protected:
Protected member is (in C++ and Java) accessible only from within the class and it’s sub classes.
How to accomplish this in Python?
The answer is _ by convention. By prefixing the name of your member with a single underscore, you’re telling others “don’t touch this, unless you’re a subclass”.
- This changes virtually nothing, you’ll still be able to access the variable from outside the class, only if you see something like this.
- you explain politely to the person responsible for this, that the variable is protected and he should not access it or even worse, change it from outside the class.
Private:
By declaring your data member private you mean, that nobody should be able to access it from outside the class, i.e. strong you can’t touch this policy.
Python supports a technique called name mangling. This feature turns every member name prefixed with at least two underscores and suffixed with at most one underscore into
_<className>_ _<memberName> ------> Name Mangling
Example:
class test:
def __init__(self): #constructor
self.x=10 #public
self._y=20 #protected
self.__z=30 #private
def m1(self): #method
print(self.x)
print(self._y)
print(self.__z)
t1=test( )
t1.m1( )
print(t1.x)
print(t1._y)
print(t1._test__z)
print(dir(t1))
Output:
10
20
30
10
20
30
['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_test__z', '_y', 'm1', 'x']
