subclass

问题 I have to match an rdd with its types. trait Fruit case class Apple(price:Int) extends Fruit case class Mango(price:Int) extends Fruit Now a dstream of type DStream[Fruit] is coming. It is either Apple or Mango . How to perform operation based on the subclass? Something like the below (which doesn't work): dStream.foreachRDD{rdd:RDD[Fruit] => rdd match { case rdd: RDD[Apple] => //do something case rdd: RDD[Mango] => //do something case _ => println(rdd.count() + "<<<< not matched anything") }

问题 Before you dive in, here is my question: how can I use type hints in a subclass to specify a different type on an instance attribute? If you are unclear on what that means, read below, where I have drawn up an example to clarify things. Full Explanation I have an abstract class Foo , and a subclass of Foo called SubclassOfFoo . Foo has an abstract method get_something that returns an object of type Something . Something has a subclass called SubclassOfSomething . SubclassOfSomething has an

问题 Before you dive in, here is my question: how can I use type hints in a subclass to specify a different type on an instance attribute? If you are unclear on what that means, read below, where I have drawn up an example to clarify things. Full Explanation I have an abstract class Foo , and a subclass of Foo called SubclassOfFoo . Foo has an abstract method get_something that returns an object of type Something . Something has a subclass called SubclassOfSomething . SubclassOfSomething has an

问题 I have the following class @dataclass_json @dataclass class Source: type: str =None label: str =None path: str = None and the two subclasses: @dataclass_json @dataclass class Csv(Source): csv_path: str=None delimiter: str=';' and @dataclass_json @dataclass class Parquet(Source): parquet_path: str=None Given now the dictionary: parquet={type: 'Parquet', label: 'events', path: '/.../test.parquet', parquet_path: '../../result.parquet'} csv={type: 'Csv', label: 'events', path: '/.../test.csv',

问题 I have the following class @dataclass_json @dataclass class Source: type: str =None label: str =None path: str = None and the two subclasses: @dataclass_json @dataclass class Csv(Source): csv_path: str=None delimiter: str=';' and @dataclass_json @dataclass class Parquet(Source): parquet_path: str=None Given now the dictionary: parquet={type: 'Parquet', label: 'events', path: '/.../test.parquet', parquet_path: '../../result.parquet'} csv={type: 'Csv', label: 'events', path: '/.../test.csv',

问题 I have a need to create a special subclass of dict. In it I want to set default values for a set of keys. I seem to be failing in finding the correct syntax to do this. Here is what I have been trying: class NewDict(dict): Key1 = "stuff" Key2 = "Other stuff" NoList = [] Nada = None I am then instantiating an object like this: PrefilledDict = NewDict() and trying to use something in there: print PrefilledDict['Key1'] But it seems that my dictionary is not a dictionary. What little bit am I

问题 I have a need to create a special subclass of dict. In it I want to set default values for a set of keys. I seem to be failing in finding the correct syntax to do this. Here is what I have been trying: class NewDict(dict): Key1 = "stuff" Key2 = "Other stuff" NoList = [] Nada = None I am then instantiating an object like this: PrefilledDict = NewDict() and trying to use something in there: print PrefilledDict['Key1'] But it seems that my dictionary is not a dictionary. What little bit am I

问题 I am trying to create a custom vectorizer by subclassing the CountVectorizer . The vectorizer will stem all the words in the sentence before counting the word frequency. I then use this vectorizer in a pipeline which works fine when I do pipeline.fit(X,y) . However, when I try to set a parameter with pipeline.set_params(rf__verbose=1).fit(X,y) , I get the following error: RuntimeError: scikit-learn estimators should always specify their parameters in the signature of their __init__ (no

问题 In the Python data model reference section on slots there is a list of notes on using __slots__ . I am thoroughly confused by the 1st and 6th items, because they seem to be contradicting each other. First item: When inheriting from a class without __slots__ , the __dict__ attribute of that class will always be accessible, so a __slots__ definition in the subclass is meaningless. Sixth item: The action of a __slots__ declaration is limited to the class where it is defined. As a result,

问题 In Objective-C there is the Alloc/Init metaphor. They've also added a shared convenience method called 'new' that internally just calls both in succession. And if I create a subclass of NSObject called FooClass, FooClass picks up those shared methods, including 'new'. BUT... how the heck is that implemented?? It can't simply delegate to the base class because that would just instantiate an instance of NSObject, not your derived class FooClass, yet it still works! So how would someone write