methods

问题 In Python, find and index are very similar methods, used to look up values in a sequence type. find is used for strings, while index is for lists and tuples. They both return the lowest index (the index furthest to the left) that the supplied argument is found. For example, both of the following would return 1 : "abc".find("b") [1,2,3].index(2) However, one thing I'm somewhat confused about is that, even though the two methods are very similar, and fill nearly the same role, just for

问题 Doing some code reading and stumbled upon this snippet that I haven't seen before: public SomeClass { public someInterface this[String strParameter] { get { return SomeInternalMethod(strParameter); } } } It looks like it is called as follows: SomeClass _someClass = new SomeClass(); SomeInterface returnedValue = _someClass["someString"]; I am interested in where this function would be appropriate or what the intent of writing in this style. For example why would this be preferred over simply

问题 I'm wondering why calls to operator methods don't require a dot? Or rather, why can't normal methods be called without a dot? Example class Foo def +(object) puts "this will work" end def plus(object) puts "this won't" end end f = Foo.new f + "anything" # "this will work" f plus "anything" # NoMethodError: undefined method `plus' for main:Object 回答1: The implementation doesn't have the additional complexity that would be needed to allow generic definition of new operators. Instead, Ruby has a

问题 I'm a VB.Net guy. (because I have to be, because the person who signs my check says so. :P) I grew up in Java and I don't generally struggle to read or write in C# when I get the chance. I came across some syntax today that I have never seen, and that I can't seem to figure out. In the following method declaration, what does < T > represent? static void Foo < T >(params T[] x) I have seen used in conjunction with declaring generic collections and things, but I can't for the life of me figure

问题 I am using Jython within a Java project. I have one Java class: myJavaClass.java and one Python class: myPythonClass.py public class myJavaClass{ public String myMethod() { PythonInterpreter interpreter = new PythonInterpreter(); //Code to write } } The Python file is as follows: class myPythonClass: def abc(self): print "calling abc" tmpb = {} tmpb = {'status' : 'SUCCESS'} return tmpb Now the problem is I want to call the abc() method of my Python file from the myMethod method of my Java

问题 Consider the two simple Java classes below: First Example class Computer { Computer() { System.out.println("Constructor of Computer class."); } void On() { System.out.println("PC turning on..."); } void working() { System.out.println("PC working..."); } void Off() { System.out.println("PC shuting down..."); } public static void main(String[] args) { Computer my = new Computer(); Laptop your = new Laptop(); my.On(); my.working(); your.On(); your.working(); my.Off(); your.Off(); } } Second

问题 I'm attempting to declare a Row and a Column class, with the Row having a private std::map with values pointing to a templated Column . Something like this: template <typename T> class DataType { private: T type; }; template <typename T> class Field { private: T value; DataType<T> type; }; class Row { private: std::map<unsigned long,Field*> column; }; Well, I suppose in principle the Row class shouldn't have to know which kind of Field (or Column ) we'd like to use, i.e. whether it's a Field

问题 Best practice to Override a class method of the gem in rails Application ? . I need to override the behaviour of the find method of a gem. following is the code in the gem module Youtube class display attr_accessor :base def find(id, options = {}) detailed = convert_to_number(options.delete(:detailed)) options[:detailed] = detailed unless detailed.nil? base.send :get, "/get_youtube", options.merge(:youtube_id => id) end end end How do i override the above find method in my YoutubeSearch

问题 I have an app, which has multiple forms. All these forms have a PopupMenu. I build the menu items programatically, all under a common root menu item. I want ALL the menu items to call the same procedure, and the menu item itself is basically acting as an argument.... I had this working when I just had one form doing this functionality. I now have multiple forms needing to do this. I am moving all my code to a common unit. Example. Form A has PopupMenu 1. When clicked, call code in Unit

问题 I can’t figure out how get this method to work: System.Windows.Input.Keyboard.IsKeyDown(System.Windows.Input.Key) The object browser says the following: public static bool IsKeyDown(System.Windows.Input.Key key) Member of System.Windows.Input.Keyboard Summary: Determines whether the specified key is pressed. Parameters: key: The specified key. Return Values: true if key is in the down state; otherwise, false. Okay, so it’s a member of Keyboard, right? I used the following code: Keyboard test