Python call class method with argument

Question

I have a class say:

class MyClass:
 def mymethod(self, data1, data2):
 print (self.data1)
 print (self.data2)

and I am calling this class somewhere in a Django view and sending this argument like:

mycls = MyClass()
mycls.mymethod(data1, data2)

When I do this it says 'MyClass' object has no attribute 'data1'

What's wrong?

Answer 1

Because you haven't assigned to them yet. I'm guessing that what you're trying to do is something like this:

class MyClass:
 def mymethod(self, data1, data2):
 self.data1 = data1
 self.data2 = data2
 print(self.data1)
 print(self.data2)

Until you actually assign to self.something (even if you have a parameter to the method called something), that variable doesn't exist. something and self.something are two different things.

Or, if you're just trying to print the values of two parameters to a method, you might want to do this instead:

class MyClass:
 def mymethod(self, data1, data2):
 print(data1)
 print(data2)

Answer 2

in MyClass.mymethod you totally ignore the data1 and data2 args and try to print the (obviously non-existant) instance attributes self.data1 and self.data2. Either it's a typo (yeah, it happens ) or you don't understand what is self in this context and the difference between arguments and attributes...

Answer 3

try this data1 you are sending and in mymethod are different :

class MyClass:
 def mymethod(self, data1, data2):
 self.data1 = data1
 self.data2 = data2
 print self.data1
 print self.data2

OR

 print data1
 print data2