Python - Define class with one method and one attribute

Question

I'm new to Python and trying create a program that defines a class called person that has one method called hello, and one attribute called name, which represents the name of the person. The hello method should print the following string to the screen:

‘My name is name attribute and I am a name of class’

1)Instantiate an object of the class, 2)Run the hello method of the instantiated object (e.g., John.hello()), 3) Use sys.argv

Here is my code:

import sys

class person():
    def __init__(self,_name):
        self.name=_name
        _name = sys.argv[1]
    def hello(self):
        print (f"My name is {sys.argv[1]} I am a {self.__class__.__name__}")

p1 = person()
p1.hello()

def main():
    p = person()
    print (type(p))

if __name__ == "__main__":
    main()

Example expected output:

My name is Obi-Wan and I am a person
<class '__main__.person'>

Actual output:

  File "classname.py", line 10, in <module>
    p1 = person()
TypeError: __init__() missing 1 required positional argument: '_name'

I don't know what I am doing wrong. Please help!

Answer 1

Your issue was that you've created a class which expects an argument, but then did not give it the requested argument. Since the __init__ function requires the _name argument, the initialization of the person class must be done with a name, for example person('my_name').

Since you get the name as an input, you probably want to save it in the class and reuse it, instead of extracting it from sys.argv every time. So the end result should look something like this-

import sys


class person():
    def __init__(self, name):
        self.name = name

    def hello(self):
        print(f"My name is {self.name} I am a {self.__class__.__name__}")


def main():
    input_name = sys.argv[1]
    p = person(input_name)
    p.hello()


if __name__ == "__main__":
    main()