subclass

问题 Ultimate goal: have isinstance(MyClass(), np.ndarray) and issubclass(MyClass, np.ndarray) both return True without MyClass calling np.ndarray.__new__() . Let's say I've implemented all the methods of numpy.ndarray and I want to set it up so that it will pass isinstance checks for ndarray , but I don't want it to actually call __new__ from ndarray . Initially, I was thinking of something like this: import numpy as np class BlockingClass(np.ndarray): def __new__(cls, *args, **kwargs): return

问题 I am attempting to sub-class Graph from the graph_tool package for some graph analysis in Python (so that I can generate some of my own functions, but still use Graph_Tool's functions as well), and I cannot seem to use graph_tool 's graph generator methods. I start by importing my classes: import graph_tool.all as gt import numpy.random as np np.seed(42) I've tried various versions of the __init__ method: Build a graph from scratch. This works, but I'd prefer not to use this, because graph

问题 Suppose I have a superclass Item and a subclass MovingItem. If I create an array of items and then try to cast one of the already created items into a MovingItem and store it in to a vector, does it mean I use a reference or I create a new object, for instance. Item[] itms = new Item[2]; itms[0] = new Item(); itms[1] = new Item(); Vector<MovingItem> movingItms = new Vector<MovingItem>(); movingItms.add((MovingItem) itms[0]); What happens when I cast the object of type Itm found in array itms

问题 i trying to get a text from a RichEdit field with WM_GETTEXT, but i run into some problems, so I found EM_STREAMOUT, this is especially for RichEdit. I found this code and played a little bit with it, but i can't get them to work: delegate uint EditStreamCallback(IntPtr dwCookie, IntPtr pbBuff, int cb, out int pcb); struct EDITSTREAM { public IntPtr dwCookie; public uint dwError; public EditStreamCallback pfnCallback; } [DllImport("user32.dll", CharSet=CharSet.Auto)] static extern IntPtr

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: How are Anonymous (inner) classes used in Java? i have a question about java. i saw this in many sources... Class object = new Class() { // What is this, a subclass or what ? public void someRandomMethod() { } }; umm if is a subclass, when i make the object the class is executed automatically ? I'm confused and sorry about my english, i try to do my best. Many thanks ! 回答1: It's called an anonymous class. Yes,

问题 We have some particular functionality implemented as a Python class, in order to be easily extended by our developers inheriting it. Each class has a an inner Config class with a list of items. The base class has an empty Config class, and each inheriting class defines some items into it. Then pylint complains each time the item of Config subclass is used. For example, this code: class A(object): class Config(object): def __init__(self): self.item1 = 1 self.item2 = 2 def __init__(self): self.

问题 I have a base class like this: package MyClass; use vars qw/$ME list of vars/; use Exporter; @ISA = qw/Exporter/; @EXPORT_OK = qw/ many variables & functions/; %EXPORT_TAGS = (all => \@EXPORT_OK ); sub my_method { } sub other_methods etc { } --- more code--- I want to subclass MyClass , but only for one method. package MySubclass; use MyClass; use vars qw/@ISA/; @ISA = 'MyClass'; sub my_method { --- new method } And I want to call this MySubclass like I would the original MyClass , and still

问题 I have a class Node. This class can add or remove other nodes relative to itself. Node is used by a List class. To prevent the nodes being modified directly (externally, IE not by the appropriate classes) during usage and causing problems with the List class, the nodes add/remove functions are either protected or private. This requires that List class is a friend to Node. However, the problem with this is that the List class itself is a template class for other subclasses, and adding

问题 I tried that: sealed trait AorB trait A extends AorB { def apiA:... } trait B extends AorB { def apiB:... } and in another file: trait C[AB<:AorB] extends AB But get an error: class type required but AB found What I actually want to do is to say that subclasses of C should implements either A or B (and not AorB which is used as some kind of trait-Enum, i.e. either A or B). Can I do that, and how? 回答1: I found the answer in one of the "related questions" proposed by SO (which had an unrelated

问题 So we have a generic method like this, which is part of dependency injection initialisation: public static <TS, TI extends TS> void registerTransient( Class<TS> serviceClass, Class<TI> implementationClass) { // } At some point we found a case where a class might not necessarily be present. And it's an implementation class which we would be injecting multiple off (so the service class is the same as the implementation class.) Naturally you would write this like this: Class<?> clazz = Class