Passing an argument to a class method

Question

I am trying to get to grips with working with objects in python and have encountered an error which is confusing me. I have added the following property to a class:

@property
def train(self, index):
 return self.make_dataset(self.train_df[index])

I want to pass it the argument 'index' so that I can call this function during a training loop. However when I try this with the following code, I get the error:

train() missing 1 required positional argument: 'index'

Even though I did pass the argument as below. I have been looking on the internet but still can't work out what the route cause of the warning is. Is this an incorrect way to mass an argument to a method?

for train_loop in range(len(train_df)):
 history = model.fit(multi_window.train(train_loop))

• chepner: train should be an ordinary method, not a property.
• Vince W.: why are you making this a property instead of a regular method?
• Charles Duffy: A property is not a regular class method. If you want to ask about properties, your question title should reflect that. If you want to ask about class methods, your question's body should actually be about regular class methods, not about properties. (@classmethod, not @property).

Answer 1

Remove the @property decorator:

def train(self, index):
 return self.make_dataset(self.train_df[index])

This will make it an instance method, callable by an object of the class (if that's what you'd like it to be).