instance | 易学教程

An enclosing instance that contains <my reference> is required

阅读更多关于 An enclosing instance that contains is required

问题 An enclosing instance that contains is required Below is the code. positionObj is the object that I am trying to use and it is giving me the above error. It\'s unclear why. package toolBox; import toolBox.Secretary.positionObj; public class PositionManagement { public static HashMap<String, Secretary.positionObj> main(String vArg){ positionObj newPosition=new positionObj(); } } 回答1: You're trying to use the non-static inner positionObj class without an instance of Secretary for it to belong

Getting an instance name inside class init() [duplicate]

阅读更多关于 Getting an instance name inside class __init__() [duplicate]

This question already has an answer here: Getting the name of a variable as a string 15 answers While building a new class object in python, I want to be able to create a default value based on the instance name of the class without passing in an extra argument. How can I accomplish this? Here's the basic pseudo-code I'm trying for: class SomeObject(): defined_name = u"" def __init__(self, def_name=None): if def_name == None: def_name = u"%s" % (<INSTANCE NAME>) self.defined_name = def_name ThisObject = SomeObject() print ThisObject.defined_name # Should print "ThisObject" Instances don't have

Python: How do I pass variables between class instances or get the caller?

阅读更多关于 Python: How do I pass variables between class instances or get the caller?

问题 class foo(): def __init__(self) self.var1 = 1 class bar(): def __init__(self): print \"foo var1\" f = foo() b = bar() In foo, I am doing something that produces \"var1\" being set to 1 In bar, I would like to access the contents of var1 How can I access var1 in the class instance f of foo from within the instance b of bar Basically these classes are different wxframes. So for example in one window the user may be putting in input data, in the second window, it uses that input data to produce

python assign values to list elements in loop

阅读更多关于 python assign values to list elements in loop

问题 Is this a valid python behavior? I would think that the end result should be [0,0,0] and the id() function should return identical values each iteration. How to make it pythonic, and not use enumerate or range(len(bar))? bar = [1,2,3] print bar for foo in bar: print id (foo) foo=0 print id(foo) print bar output: [1, 2, 3] 5169664 5169676 5169652 5169676 5169640 5169676 [1, 2, 3] 回答1: First of all, you cannot reassign a loop variable—well, you can, but that won’t change the list you are

“No enclosing instance of type” error while calling method from another class in Android

阅读更多关于 “No enclosing instance of type” error while calling method from another class in Android

问题 Colleagues, I have the such question: 1. In my first class I have the public class parseYouTubeAndYahoo extends AsyncTask<String, Void, List<VideoDataDescription>> to parse data from internet. But I need to call execute() method of this class from another class. While trying to right such code: new MainActivity.parseYouTubeAndYahoo().execute(\"someURL\"); I have the next error message from Eclipse No enclosing instance of type MainActivity is accessible. Must qualify the allocation with an

Instance new Type (Golang)

阅读更多关于 Instance new Type (Golang)

问题 Can anyone tell me how to create a new instance of Type from a string? Reflect? There are examples but they are for the older (pre Go 1 versions) of the language [:(] 回答1: So, if I understand your question correctly, you are asking about how you can create an object when you just have the name of the type as string. So, for example, you might have a string "MyStruct" and you want to create an object of this type. Unfortunately, that's not easily possible because Go is a statically typed

Java: newInstance of class that has no default constructor

阅读更多关于 Java: newInstance of class that has no default constructor

问题 I\'m trying to build an automatic testing framework (based on jUnit, but that\'s no important) for my students\' homework. They will have to create constructors for some classes and also add some methods to them. Later, with the testing functions I provide, they will check if they went alright. What I want to do is, by reflection , create a new instance of some class I want to test. The problem is that, sometimes, there is no default constructor . I don\'t care about that, I want to create an

Java Static vs Instance

阅读更多关于 Java Static vs Instance

So my coder friend hates using the static coding. Yet my Java program is full of it to link between classes, and I have a lot of them! Is it worth rewriting the whole code to remove the static method? Is there any advantage of using one over the other? Kumar Vivek Mitra 1. An instance variable is one per Object , every object has its own copy of instance variable. Eg: public class Test{ int x = 5; } Test t1 = new Test(); Test t2 = new Test(); Both t1 and t2 will have its own copy of x . 2. A static variable is one per Class , every object of that class shares the same Static variable. Eg:

What makes a jQuery object show up as an array in Chrome's Developer Tools?

阅读更多关于 What makes a jQuery object show up as an array in Chrome's Developer Tools?

问题 I\'m wondering how it\'s possible that jQuery objects show up as an array in the console log of Developer Tools in Chrome. E.g. if I execute $(\'<a>\') , what I see in the console log is: [<a></a>] But the following statements are false: var a = $(\"<a>\"); Array.isArray(a); // false a instanceof Array; // false I tried to modify jQuery and see what happens, and one thing that was surprising is that removing length from the jQuery function removes the array notation: length: 0, //

Python object deleting itself

阅读更多关于 Python object deleting itself

问题 Why won\'t this work? I\'m trying to make an instance of a class delete itself. >>> class A(): def kill(self): del self >>> a = A() >>> a.kill() >>> a <__main__.A instance at 0x01F23170> 回答1: 'self' is only a reference to the object. 'del self' is deleting the 'self' reference from the local namespace of the kill function, instead of the actual object. To see this for yourself, look at what happens when these two functions are executed: >>> class A(): ... def kill_a(self): ... print self ...