How do you call a method from inside another method in the same class?

Question

BlackTom AI · Accepted Answer

Instance methods are invoked on the current instance, so you call another instance method using self.method(). This works because self inside an instance method is the reference to the particular object and Python binds methods to instances automatically.

1) Relevant concepts
- Instance methods receive the instance as the first parameter (conventionally named self).
- Accessing a method via self (e.g., self.method) returns a bound method: the function together with the instance, so calling it automatically passes self.
- Unqualified method() looks for a free function or a local name, not the instance method. __class__.method is an unbound function on the class and requires an explicit instance argument. super.method() is syntactically incorrect; super() is a callable returning a proxy and must be used as super().method(...).

2) Step-by-step reasoning
- Given class C with def a(self): and def b(self):, inside b you want to call a.
- Writing self.a() resolves attribute lookup on the instance: instance.__getattribute__('a') returns a bound method object, so calling it executes a with self passed automatically.
- Writing a() tries to call a name a in the current scope; since no such local, Python raises NameError.
- Writing __class__.a() refers to the function object on the class; that function expects an explicit instance argument, so calling __class__.a() inside a method will raise TypeError (missing 1 required positional argument: 'self') unless you supply __class__.a(self).
- Writing super.method() is incorrect; the correct usage would be super().method(), which would call the method resolved from the parent class and also returns a bound method that will receive self.

3) Example (illustrative)
class C:
    def a(self):
        print("a")
    def b(self):
        self.a()   # correct: calls a with self automatically

4) Why the correct answer is correct
self.method() uses the instance to retrieve a bound method so the self parameter is automatically provided; this is the idiomatic and straightforward way to call another instance method.

5) Why other options are incorrect
- __class__.method(): yields an unbound function; you must pass self explicitly (e.g., __class__.method(self)).
- method(): tries to call a local/global name; not the instance method, so NameError.
- super.method(): wrong syntax; should be super().method(), and even then it targets the superclass method, not necessarily the same-class instance method.

Conclusion: The correct choice is self.method(), which matches the provided answer.

How do you call a method from inside another method in the same class?单项选择题

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