A bound method is the one which is dependent on the instance of the class as the first argument. It passes the instance as the first argument which is used to access the variables and functions. In Python 3 and newer versions of python, all functions in the class are by default bound methods.
Let’s understand this concept with an example:
class A:
def func( self , arg):
self .arg = arg
print ( "Value of arg = " , arg)
obj = A()
print (obj.func)
|
Output:
< bound method A.func of <__main__.A object at 0x7fb81c5a09e8>>
Here,
obj.func(arg) is translated by python as A.func(obj, arg).
The instance obj
is automatically passed as the first argument to the function called and hence the first parameter of the function will be used to access the variables/functions of the object.
Let’s see another example of the Bound method.
class Car:
gears = 5
@classmethod
def change_gears( cls , gears):
cls .gears = gears
Car1 = Car()
print ( "Car1 gears before calling change_gears() = " , Car1.gears)
Car1.change_gears( 6 )
print ( "Gears after calling change_gears() = " , Car1.gears)
print (Car1.change_gears)
|
Output:
Car1 gears before calling change_gears() = 5
Gears after calling change_gears() = 6
<bound method Car.change_gears of <class '__main__.Car'>>
The above code is an example of a classmethod. A class method is like a bound method except that the class of the instance is passed as an argument rather than the instance itself. Here in the above example when we call Car1.change_gears(6)
, the class ‘Car’ is passed as the first argument.
Last Updated :
11 Dec, 2019
Like Article
Save Article
Share your thoughts in the comments
Please Login to comment...