class

问题 I am writing a class where I need to check whether the instance variables are of a certain type. I noticed that there is a lot of repeating code. Is there a better way to do similar checks on the instance variables? Or is this the right way to do it? class Variable(): __type = 'Variable' def __init__(self, id = None, updateable = True, name = 'Variable', value=None): if id is not None: self.id = id if value is not None: self.value = value self.updateable = updateable self.name = name

问题 Is there a way to make a class return one of its fields by default like that: public class TestClass { public string something; } TestClass test = new TestClass(); test = "alpha"; // "alpha" string is assigned to "something" Console.Write(test); // test returns "alpha" string from "something" How to make this work? 回答1: For all those saying that's impossible,) public class TestClass { public string something; public static implicit operator TestClass(string s) => new TestClass { something = s

问题 Why would I want to add anything to a class using class << Class syntax? class Fun def much_fun # some code here end end class << Fun # the difference is here! def much_more_fun # some code here end end instead of using the monkey patching/duck punching method: class Fun def much_fun # some code here end end class Fun # the difference is here! def much_more_fun # some code here end end While reading Why's Poignant Guide to Ruby I came across: Why defines a class LotteryDraw : class

问题 Why would I want to add anything to a class using class << Class syntax? class Fun def much_fun # some code here end end class << Fun # the difference is here! def much_more_fun # some code here end end instead of using the monkey patching/duck punching method: class Fun def much_fun # some code here end end class Fun # the difference is here! def much_more_fun # some code here end end While reading Why's Poignant Guide to Ruby I came across: Why defines a class LotteryDraw : class

问题 I'm experienced in Python and now learning cpp to speed up code. After reading a bit this seems to be the cpp equivalent of self . I found a question explaining the difference from a cpp user's point of view but I'd like to know any differences for a python user's point of view. 回答1: The major difference is that you mostly don't need this in C++, because there is a syntactic distinction between defining a member and referring to it. Contrast Python: class Foo: def __init__(self): self._bar =

问题 I'm experienced in Python and now learning cpp to speed up code. After reading a bit this seems to be the cpp equivalent of self . I found a question explaining the difference from a cpp user's point of view but I'd like to know any differences for a python user's point of view. 回答1: The major difference is that you mostly don't need this in C++, because there is a syntactic distinction between defining a member and referring to it. Contrast Python: class Foo: def __init__(self): self._bar =

问题 I'm experienced in Python and now learning cpp to speed up code. After reading a bit this seems to be the cpp equivalent of self . I found a question explaining the difference from a cpp user's point of view but I'd like to know any differences for a python user's point of view. 回答1: The major difference is that you mostly don't need this in C++, because there is a syntactic distinction between defining a member and referring to it. Contrast Python: class Foo: def __init__(self): self._bar =

问题 I'm creating a package with some classes that I generated with wsimport on the fly and now I'm trying to load it to use, how can I do this? natively? or with some lib like byte-buddy, I tried the bellow code to load each class in a package: File [] files = new File("<Path to package in filesystem with classes (*.class)>").listFiles(); List<URL> classUrls = new ArrayList<>(); for(File file : files) { classUrls.add(new URL("file://" + file.getAbsolutePath())); } URL[] classz = new URL[classUrls

问题 Let's say we have a base class: public abstract class BaseFragment extends Fragment { ... protected abstract boolean postExec(); ... } And then derive from it to have other class(es) (e.g. Fragment_Movie, Fragment_Weather ...) public class Fragment_Music extends BaseFragment{ @Override protected boolean postExec() { return false; } } However, when adding a new method to the base class: public abstract class BaseFragment extends Fragment { ... protected abstract boolean postExec(); protected

问题 In c++ we know that for a pointer of class we use (->) arrow operator to access the members of that class like here: #include <iostream> using namespace std; class myclass{ private: int a,b; public: void setdata(int i,int j){ a=i; b=j; } }; int main() { myclass *p; p = new myclass; p->setdata(5,6); return 0; } Then I create a array of "myclass". p=new myclass[10]; but then, when I go to access myclass members through (->) arrow operator, I get following error base operand of '->' has non