self keyword in python

1self represents the instance of the class. By using the “self” keyword we can access the attributes and methods of the class in python. It binds the attributes with the given arguments. 

1"""
2
3Before potentially reading along I highly suggest you master how to
4use parameters and arguments in python because if you haven't this can
5get confusing. Otherwise read along:
6
7The self argument is most frequently used in the __init__ function.
8
9The __init__ function is a constructor function meaning that it 
10constructs objects in a class.
11
12This is part of the object oriented programming (OOP) branch.
13
14In this example ill be creating a person with values of name, gender and
15age.
16
17What 'self' essentailly is, is the class, so when referring to 'self'
18you are refering to values in a class.
19
20So 'self.age = age' is just adding a variable in the
21class which has the same value as 'age'.
22
23"""
24
25# Creating the class
26class Person:
27  # Creating the constructor method
28  def __init__(self, name, age, gender):
29    # defining variables
30    self.name = name
31    self.age = age
32    self.gender = male
33
34# Creating Objects 
35Person1 = Person("Isabella", 27, "female")
36Person2 = Person("Mikkel", 29, "male")
37
38# Creating a list of people:
39People = [ Person1, Person2 ]
40
41"""
42
43You can now use the list of people to well.. list people and their
44details.
45
46You could make a table of people by making the array 2 dimensional
47which can eventually lead to a database, 
48but this isn't a post to get into that.
49
50"""
51"""
52
53Thats essentially how to use constructors, you're creating an object
54relative to topic per se. More examples / usages:
55
56"""
57
58class Person:
59  def __init__(self, name, age, gender):
60    # The 3 arguments can only be used within this function
61    # So you must attach it to the class using 'self'
62    self.name = name
63    self.age = age
64    self.gender = gender
65  
66  def Function(self):
67    # To be able to use it all around the class.
68    print(self.name)
69    print(self.age)
70
71P = Person("Jeff", 27, "male")
72
73P.Function()
74# Output:
75# >>> Jeff
76# >>> 27
77
78#Or
79
80print(P.name)
81print(P.age)
82# Output:
83# >>> Jeff
84# >>> 27
85
86
87"""
88
89So overall this comes to show that self.something is the exact same as
90a varible but rather than a global variable or a variable within a
91function scope, it's instead a class variable.
92
93So when doing 'self.something' logically you can think of it as:
94'class.something'
95
96And thats it. To see a better way of coding the code above you can
97carry on reading but although it's not necessary to know.
98
99
100
101A better way of calling a class is to use the __call__ method.
102
103This creates an inbuilt constant function within the class that can be
104called, rather than creating a function as above.
105
106"""
107
108class Person:
109  
110  def __init__(self, name, age, gender):
111    self.name=name
112    self.age=age
113    self.gender=gender
114   
115  def __call__(self):
116    print(self.name)
117    print(self.age)
118
119# Creating the object
120P = Person("Jeff", 27, "male")
121
122# Calling the call function:
123P()
124# Output:
125# >>> Jeff
126# >>> 27
127
128# This makes everything much neater and compact.
129
130# Have a wonderful day :)

1class Class(parentClass):
2    def __init__(self,arg):
3        self.arg = arg
4        
5    def function(self):
6        print(arg)

1class Person:
2  def __init__(mysillyobject, name, age):
3    mysillyobject.name = name
4    mysillyobject.age = age
5
6  def myfunc(abc):
7    print("Hello my name is " + abc.name)
8
9p1 = Person("John", 36)
10p1.myfunc()
11
12#self represents the instance of the class. By using the “self” keyword we can access the attributes and methods of the class in python. It binds the attributes with the given arguments. The reason you need to use self. is because Python does not use the @ syntax to refer to instance attributes