clone

问题 This code (playground): #[derive(Clone)] struct Foo<\'a, T: \'a> { t: &\'a T, } fn bar<\'a, T>(foo: Foo<\'a, T>) { foo.clone(); } ... does not compile: error: no method named `clone` found for type `Foo<\'a, T>` in the current scope --> <anon>:7:9 |> 16 |> foo.clone(); |> ^^^^^ note: the method `clone` exists but the following trait bounds were not satisfied: `T : std::clone::Clone` help: items from traits can only be used if the trait is implemented and in scope; the following trait defines

问题 The Ruby docs for dup say: In general, clone and dup may have different semantics in descendent classes. While clone is used to duplicate an object, including its internal state, dup typically uses the class of the descendent object to create the new instance. But when I do some test I found they are actually the same: class Test attr_accessor :x end x = Test.new x.x = 7 y = x.dup z = x.clone y.x => 7 z.x => 7 So what are the differences between the two methods? 回答1: Subclasses may override

问题 I\'ve got a generic dictionary Dictionary<string, T> that I would like to essentially make a Clone() of ..any suggestions. 回答1: Okay, the .NET 2.0 answers: If you don't need to clone the values, you can use the constructor overload to Dictionary which takes an existing IDictionary. (You can specify the comparer as the existing dictionary's comparer, too.) If you do need to clone the values, you can use something like this: public static Dictionary<TKey, TValue> CloneDictionaryCloningValues

问题 I need clarification on the differences between deep copy, shallow copy, and clone in Java 回答1: Unfortunately, "shallow copy", "deep copy" and "clone" are all rather ill-defined terms. In the Java context, we first need to make a distinction between "copying a value" and "copying an object". int a = 1; int b = a; // copying a value int[] s = new int[]{42}; int[] t = s; // copying a value (the object reference for the array above) StringBuffer sb = new StringBuffer("Hi mom"); // copying an

问题 I need to clone the id and then add a number after it like so id1 , id2 , etc. Everytime you hit clone you put the clone after the latest number of the id. $(\"button\").click(function() { $(\"#id\").clone().after(\"#id\"); }); 回答1: $('#cloneDiv').click(function(){ // get the last DIV which ID starts with ^= "klon" var $div = $('div[id^="klon"]:last'); // Read the Number from that DIV's ID (i.e: 3 from "klon3") // And increment that number by 1 var num = parseInt( $div.prop("id").match(/\d+/g

问题 I\'m relatively new to Git, but I\'ve found it so easy to work with at home that I\'d like to use it at work where our projects are stored in Svn repositories. Unfortunately, the repositories are slightly non-standard and I\'m having trouble getting them cloned. Sure, they all have trunk, branches/ and tags/, but branches/ and tags/ have subdirectories before hitting the real project directories: trunk/ branches/maintenance/release1 branches/maintenance/release2 ... branches/development

问题 What is the specific reason that clone() is defined as protected in java.lang.Object ? 回答1: The fact that clone is protected is extremely dubious - as is the fact that the clone method is not declared in the Cloneable interface. It makes the method pretty useless for taking copies of data because you cannot say : if(a instanceof Cloneable) { copy = ((Cloneable) a).clone(); } I think that the design of Cloneable is now largely regarded as a mistake (citation below). I would normally want to be

问题 I have a generic list of objects in C#, and wish to clone the list. The items within the list are cloneable, but there doesn\'t seem to be an option to do list.Clone() . Is there an easy way around this? 回答1: You can use an extension method. static class Extensions { public static IList<T> Clone<T>(this IList<T> listToClone) where T: ICloneable { return listToClone.Select(item => (T)item.Clone()).ToList(); } } 回答2: If your elements are value types, then you can just do: List<YourType> newList

问题 I want to understand the difference between a branch, a fork and a clone in Git? Similarly, what does it mean when I do a git fetch as opposed to a git pull ? Also, what does rebase mean in comparison to merge ? How can I squash individual commits themselves together? How are they used, why are they used and what do they represent? How does GitHub figure in? 回答1: A clone is simply a copy of a repository. On the surface, its result is equivalent to svn checkout , where you download source code

问题 I have an object, x . I\'d like to copy it as object y , such that changes to y do not modify x . I realized that copying objects derived from built-in JavaScript objects will result in extra, unwanted properties. This isn\'t a problem, since I\'m copying one of my own, literal-constructed objects. How do I correctly clone a JavaScript object? 回答1: To do this for any object in JavaScript will not be simple or straightforward. You will run into the problem of erroneously picking up attributes