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Table Of Contents:
- What Is A Magic Function?
- Examples Of Magic Methods.
- Know The Magic Methods Inside The Class.
(1) What Is A Magic Function?
- Magic methods in Python are the special methods that start and end with double underscores( __ ).
- They are also called dunder methods because they use double underscores(__).
- Magic methods are not designed to be invoked by the user, but the invocation happens internally from the class on a specific action.
- For example, when you initialize a class the __init__ method will be called automatically.
- Here __init__ method is called a magic method because it is hiddenly called by the compiler itself.
(2) Examples Of Magic Function?
Example-1
class Student:
def __init__(self,name,rollno):
self.name = name
self.rollno = rollno
def details(self):
print('Student Name:',self.name)
print('Student Roll No:',self.rollno)obj = Student('Abhispa',34)
obj.details()Output:
Student Name: Abhispa
Student Roll No: 34Note:
- Here you can notice that I have not called the __init__ method, but it’s been automatically called.
- So this is the magic of the Magic Method.
Example-2
class addition:
def __add__(self,number):
return 5 + numberobj = addition()
print(obj + 10)Output:
15Note:
- Here you can notice that I have not called the __add__ method, but it’s been automatically called.
- So this is the magic of the Magic Method.
Example-3
class Bikes:
def __new__(self,name):
print('I Have A New Bike.')
inst = object.__new__(self)
return inst
def __init__(self,name):
self.name = name
print(f'I Have A {self.name} Bike.')obj = Bikes('Ninja')Output:
I Have A New Bike.
I Have A Ninja Bike.Note:
- Here you can notice that the __new__ method is first called and then the __init__ method.
- Here __new__ and __init__ methods are the magic method.
So this is the magic of the Magic Method.
(3) Know The Magic Methods Inside The Class.
- The inbuilt dir( ) method is used to know the number of magic methods inherited by a class.
- You need to pass the class name to the dir( ) method to get the list of magic methods.
Example-1
dir(str)Output:
['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__',
'__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__',
'__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__',
'__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__',
'__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__',
'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs',
'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isascii', 'isdecimal',
'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle',
'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'removeprefix',
'removesuffix','replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split',
'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']Example-2
dir(int)Output:
['__abs__', '__add__', '__and__', '__bool__', '__ceil__', '__class__', '__delattr__',
'__dir__', '__divmod__', '__doc__', '__eq__', '__float__', '__floor__', '__floordiv__',
'__format__', '__ge__', '__getattribute__', '__getnewargs__', '__gt__', '__hash__',
'__index__', '__init__', '__init_subclass__', '__int__', '__invert__', '__le__',
'__lshift__', '__lt__', '__mod__', '__mul__', '__ne__', '__neg__', '__new__',
'__or__', '__pos__', '__pow__', '__radd__', '__rand__', '__rdivmod__', '__reduce__',
'__reduce_ex__', '__repr__', '__rfloordiv__', '__rlshift__', '__rmod__', '__rmul__',
'__ror__', '__round__', '__rpow__', '__rrshift__', '__rshift__', '__rsub__',
'__rtruediv__', '__rxor__', '__setattr__', '__sizeof__', '__str__', '__sub__',
'__subclasshook__', '__truediv__', '__trunc__', '__xor__', 'as_integer_ratio',
'bit_length', 'conjugate', 'denominator', 'from_bytes', 'imag', 'numerator', 'real', 'to_bytes']