What is bound and unbound method in python

Question

what is exactly bound method and unbound method in python. How does it differ when object is created?

i am beginner to python i wrote this small piece of code

   class newclass:
      def function1(self,var2):
        self.var2=var2
        print var2
        self.fun_var=var2

   newobject = newclass
   newobject.function1(64)

I am getting error like this

Traceback (most recent call last):
  File "basic_class.py", line 8, in <module>
    newobject.function1(64)
TypeError: unbound method function1() must be called with newclass instance as first argument (got int instance instead)

what is exactly bound method and unbound method in python

score 2 · Answer 1 · edited May 23 '17 at 11:45

2

The correct object initialization in Python is:

newobject = newclass()   # Note the parens

A bound method is an instance method, ie. it works on an object. An unbound method is a simple function that can be called without an object context. See this answer for a detailed discussion.

Note that in Python 3 unbound method concept is removed.

edited May 23 '17 at 11:45

Community

1
1

answered Feb 09 '16 at 12:30

Selcuk

57,004
12
102
110

score 2 · Answer 2 · answered Feb 09 '16 at 12:32

2

In your case you should first create instance of newclass and then call function1.

class newclass:
  def function1(self,var2):
    self.var2=var2
    print var2
    self.fun_var=var2

newobject = newclass
newobject().function1(64)

answered Feb 09 '16 at 12:32

ikhtiyor

504
5
15

What is bound and unbound method in python

2 Answers2