default-value

setting a default value to an undefined variable in javascript

由 十年热恋 提交于 2019-12-09 17:30:16
问题 Ideally I want to be able to write something like: function a( b ) { b.defaultVal( 1 ); return b; } The intention of this is that if b is any defined value, b will remain as that value; but if b is undefined, then b will be set to the value specified in the parameter of defaultVal() , in this case 1 . Is this even possible? Ive been toying about with something like this: String.prototype.defaultVal=function(valOnUndefined){ if(typeof this==='undefined'){ return valOnUndefined; }else{ return

how to set default method argument values? [duplicate]

由 假如想象 提交于 2019-12-09 14:42:40
问题 This question already has answers here : Does Java support default parameter values? (20 answers) Closed 6 years ago . Is it possible to set the default method parameter values in Java? Example: If there is a method public int doSomething(int arg1, int arg2) { //some logic here return 0; } is it possible to modify the given method in order to be able to call it with and without parameters? example: doSomething(param1, param2); doSomething(); Thanks! 回答1: You can accomplish this via method

Default value of a type in javascript

由 萝らか妹 提交于 2019-12-09 11:39:31
问题 Is there a function in JavaScript that returns the default value for a type name that is passed to it? For example: var defaultValue = built_in_getDefaultValue("number"); console.log(defaultValue); // Logs the number 0 to the console. 回答1: Both of the answers correctly note that the default (unassigned) value of a variable in JavaScript is undefined , but neither addresses what you seem to be looking for—an equivalent of e.g. the default operator in C#. Fortunately, JavaScript has a very

Sourcesafe command line options

由 谁说胖子不能爱 提交于 2019-12-09 11:39:29
问题 I am having an issue with the Microsoft Visual Sourcesafe command line options that I'm hoping someone has run across and can assist me with. I have the following line in a DOS batch file. "c:\Program Files\Microsoft Visual SourceSafe\ss.exe" GET "$/Development Projects/Activity" -GL"C:\Compile\Activity" -R -Q -Yname,password When this line is executed in the batch file the following prompt appears ... Set C:\Compile\Activity as the default folder for project $/Development Projects/Activity?

How to set default value for Auto-Implemented Properties in ASP.NET [duplicate]

由 十年热恋 提交于 2019-12-09 07:41:15
问题 This question already has answers here : What is the best way to give a C# auto-property an initial value? (22 answers) Closed 5 years ago . I came to know that C# 3.0 comes with a new feature of Auto-Implemented Properties,I liked it as we don't have to declare extra private varible in this (compare to earlier property), earlier I was using a Property i.e. private bool isPopup = true; public bool IsPopup { get { return isPopup; } set { isPopup = value; } } Now I've converted it into Auto

Record syntax default value for accessor

由 主宰稳场 提交于 2019-12-09 02:54:58
问题 As I was writing up an answer just now, I ran across an interesting problem: data Gender = Male | Female deriving (Eq, Show) data Age = Baby | Child | PreTeen | Adult deriving (Eq, Show, Ord) data Clothing = Pants Gender Age | Shirt Gender Age | Skirt Age -- assumed to be Female deriving (Show, Eq) Suppose I wish to write the final data type with record syntax: data Clothing = Pants {gender :: Gender, age :: Age} | Shirt {gender :: Gender, age :: Age} | Skirt {age :: Age} deriving (Show, Eq)

Why do we have to specify <> for a template class with default parameters?

由 蓝咒 提交于 2019-12-08 19:12:19
问题 I find something annoying in C++ and I don't know if there is a trick to avoid this with no overhead. The problem is the following : For a template function, we can have : // Function declaration/definition template<bool Option = false> void myFunction() { std::cout<<"Option = "<<Option<<std::endl; } // Then I can use : myFunction<false>(); myFunction<true>(); myFunction(); // <- NO PROBLEM HERE Now for a template class : // Class definition/declaration template<bool Option = false> class

Mutable HashMap with a mutable default value doesn't keep the changes [duplicate]

由 我怕爱的太早我们不能终老 提交于 2019-12-08 13:07:21
问题 This question already has an answer here : Update mutable HashMap value which is a mutable collection (1 answer) Closed last year . Suppose that I want a mutable HashMap[Int, HashSet[Int]] that has integers as keys mutable hash sets of integers as values I want that an empty mutable HashSet is created by default whenever a value for a new key is accessed or updated. Here is what I tried: import collection.mutable.{HashMap, HashSet} val hm = HashMap .empty[Int, HashSet[Int]] .withDefault(_ =>

How to specifiy enumeration literal as default value in UML Attribute?

由 女生的网名这么多〃 提交于 2019-12-08 11:26:27
I currently doing some model transformations using EMF-UML-Implementation. In my model transformation I create an uml class with some attributes. The attributes are type of enumerations I also created. Some of the attribute should get a default value. The default value should be enumeration literals. The question now is, how do I get the enumeration literals to the defaultValue -property of the Property . I already have found that I have to use ValueSpecification . But the UML superstructure says not much about that (page 139 f.). Which properties do I have to use for setting the defaultValue

Preselect radio button in Struts2

由 淺唱寂寞╮ 提交于 2019-12-08 05:07:44
问题 Using Struts2, I have a very simple radio tag like following <s:radio label="correctOption" name="correctAnswer" list=" #{'1':'1','2':'2','3':'3','4':'4'}" value="questionVo.correctAnswer"/> questionVo.correctAnswer returns 2 . So I want the second radio button to be preselected but it is not happening. I even tried: <s:radio label="correctOption" name="correctAnswer" list=" #{'1':'1','2':'2','3':'3','4':'4'}" value="%{1}"/> But that does not work either. What am I doing wrong? 回答1: Remove
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