python global name self is not defined

Question

Just started learning python and I am sure its a stupid question but I am trying something like this       def setavalue self           self myname    harry       def printaname            print  Name   self myname           def main            printname           if   name         main             main      The error I am getting is    NameError  global name  self  is not defined   I saw this way of using the self statement to reference variables of different methods in some code I read that is working fine   Thanks for the help

User · Answer

If you come from a language such as Java maybe you can make some kind of association between self and this. self will be the reference to the object that called that method but you need to declare a class first. Try:

class MyClass(object)

    def __init__(self)
        #equivalent of constructor, can do initialisation and stuff


    def setavalue(self):
        self.myname = "harry"

    def printaname(self):
        print "Name", self.myname     

def main():
    #Now since you have self as parameter you need to create an object and then call the method for that object.
    my_obj = MyClass()
    my_obj.setavalue() #now my_obj is passed automatically as the self parameter in your method declaration
    my_obj.printname()


if __name__ == "__main__":
    main()

You can try some Python basic tutorial like here: Python guide

User · Answer

In Python self is the conventional name given to the first argument of instance methods of classes  which is always the instance the method was called on   class A object     def f self       print self  a   A   a f     Will give you something like   lt   main   A object at 0x02A9ACF0 gt

User · Answer

self is the self-reference in a Class  Your code is not in a class  you only have functions defined   You have to wrap your methods in a class  like below  To use the method main    you first have to instantiate an object of your class and call the function on the object    Further  your function setavalue should be in   init     the method called when instantiating an object  The next step you probably should look at is supplying the name as an argument to init  so you can create arbitrarily named objects of the Name class      class Name      def   init   self           self myname    harry       def printaname self           print  Name   self myname           def main self           self printaname    if   name         main         objName   Name       objName main      Have a look at the Classes chapter of the Python tutorial an at Dive into Python for further references

User · Answer

The self name is used as the instance reference in class instances  It is only used in class method definitions  Don t use it in functions    You also cannot reference local variables from other functions or methods with it  You can only reference instance or class attributes using it

User · Answer

It should be something like   class Person     def setavalue self  name                  self myname   name          def printaname self                  print  Name   self myname             def main       p   Person      p setavalue  harry      p printaname

[python] python global name 'self' is not defined

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