enumeration

问题 I'm doing a base 64 permutation incrementor. I've already written all the working code. But seeing as how Ruby already as Array::permutation which produces an Enumerator; I'd like to use that and take it a step further. Without having to go through every permutation by using 'next', can I set the start point? x = ('A'..'Z').to_a + ('a'..'z').to_a + ('0'..'9').to_a + ['+','/'] y = x.permutation(12) y.peek.join => "ABCDEFGHIJKL" y.next y.peek.join => "ABCDEFGHIJKM" . # DO SOMETHING LIKE THIS y

问题 I want to automatically convert/coerce strings into Scala Enumeration Values, but without knowing beforehand what Enumeration subclass (subobject?) the declaration is from. So, given: object MyEnumeration extends Enumeration { type MyEnumeration = Value val FirstValue, SecondValue = Value } and class MyThing { import MyEnumeration._ var whichOne: MyEnumeration = FirstValue } how would I implement the following? val myThing = new MyThing() setByReflection(myThing, "whichOne", "SecondValue")

问题 I'm trying to log the contents of the HttpServletRequest attributes collection. I need to do this when the servlet first starts, and again right before the servlet is finished. I'm doing this in an attempt to understand a crufty and ill-maintained servlet. Because I need to have as little impact as possible, servlet filters are not an option. So here's the problem. When the servlet starts, I'll iterate through the enumeration returned by HttpServletRequest.getAttributeNames(). However, when I

问题 In what usages of Object.create do you want to set enumerable to true ? 回答1: A property of an object should be enumerable if you want to be able to have access to it when you iterate through all the objects properties. Example: var obj = {prop1: 'val1', prop2:'val2'}; for (var prop in obj){ console.log(prop, obj[prop]); } In this type of instantiation, enumerable is always true, this will give you an output of: prop1 val1 prop2 val2 If you would have used Object.create() like so: obj = Object

问题 Forward declaration of enums in C does not work for me. I searched the internet and stackoverflow but all of the questions regarding forward declarations of enumerators refer to c++. What do you do for declaring enumerators in C? Put them at the top of each file (or in an include) so that all functions in the file can access them? Thanks 回答1: Put them in a header so that all files that need them can access the header and use the declarations from it. When compiled with the options: $ /usr/bin

问题 Given a seed string, I want to find its neighbors with at most differ in 2 positions. All the digits involve in generating string are only four (i.e. 0,1,2,3). This is the example for what I mean: # In this example, 'first' column # are neighbors with only 1 position differ. # The rest of the columns are 2 positions differ Seed = 000 100 110 120 130 101 102 103 200 210 220 230 201 202 203 300 310 320 330 301 302 303 010 011 012 013 020 021 022 023 030 031 032 033 001 002 003 Seed = 001 101

问题 Given the following example: <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"> <xs:complexType name="Book" abstract="true"> <xs:sequence> <xs:element name="titel" type="xs:string"> </xs:element> <xs:element name="bookCode" type="BookEnum"/> </xs:sequence> </xs:complexType> <xs:complexType name="Lyric"> <xs:complexContent> <xs:extension base="Book"> <xs:sequence> <xs:element name="author" type="xs:string"> </xs:element> </xs:sequence> </xs:extension> </xs:complexContent> </xs:complexType

问题 Using the Typinfo unit, it is easy to enumerate properties as seen in the following snippet: procedure TYRPropertiesMap.InitFrom(AClass: TClass; InheritLevel: Integer = 0); var propInfo: PPropInfo; propCount: Integer; propList: PPropList; propType: PPTypeInfo; pm: TYRPropertyMap; classInfo: TClassInfo; ix: Integer; begin ClearMap; propCount := GetPropList(PTypeInfo(AClass.ClassInfo), propList); for ix := 0 to propCount - 1 do begin propInfo := propList^[ix]; propType := propInfo^.PropType; if

问题 Is there a way to enumerate the items in a list within mockito's thenReturn function so I return each item in a list. So far I've done this: List<Foo> returns = new ArrayList<Foo>(); //populate returns list Mockito.when( /* some function is called */ ).thenReturn(returns.get(0), returns.get(1), returns.get(2), returns.get(3)); This works exactly how I want it to. Each time the function is called, it returns a different object from the list, e.g get(1) , get(2) etc. But I want to simplify this

问题 I'm writing a servlet, and need to get all parameters from the request. I found request.getParameterNames returns a java.util.Enumeration , so I have to write code as: val names = request.getParameterNames while(names.hasMoreElements) { val name = names.nextElement } I wanna know is there any way to convert a Enumeration to a Seq/List , then I can use the map method? 回答1: You can build it yourself like this val nameIterator = Iterator.continually((names, names.nextElement)).takeWhile(_._1