iterator | 易学教程

How to iterate through a Map in java?

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问题 I need to iterate through a BucketMap and get all keys but how do I get to something like buckets[i].next.next.next.key for instance without doing it manually as I tried here: public String[] getAllKeys() { int j = 0; //index of string array "allkeys" String allkeys[] = new String[8]; for(int i = 0; i < buckets.length; i++) { //iterates through the bucketmap if(buckets[i] != null) { //checks wether bucket has a key and value allkeys[j] = buckets[i].key; //adds key to allkeys j++; // counts up

What is “>>>” operator in JS? [duplicate]

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问题 This question already has answers here : Closed 8 years ago . Possible Duplicate: javascript >>> operator? JavaScript triple greater than Found this operator in such line of code: var t = Object(this), len = t.length >>> 0; What does this operator mean? Full code is below. It is the code of JS some method: if (!Array.prototype.some) { Array.prototype.some = function(fun /*, thisp */) { "use strict"; if (this == null) throw new TypeError(); var t = Object(this), len = t.length >>> 0; if

What is “>>>” operator in JS? [duplicate]

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In Rust, what's the idiomatic way to split a &str into an iterator of &strs of one character each?

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问题 If I want to take a &str like "aeiou" and turn it into an iterator roughly equivalent to ["a", "e", "i", "o", "u"].iter() , what's the most idiomatic way to do it? I've tried doing "aeiou".split("") which seemed idiomatic to me, but I got empty &str s at the beginning and end. I've tried doing "aeiou".chars() but it got pretty ugly and unwieldy from there trying to turn the char s into &str s. For the time being, I just typed out ["a", "e", "i", "o", "u"].iter() , but there's got to be an

In Rust, what's the idiomatic way to split a &str into an iterator of &strs of one character each?

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java学习-hashMap和linkedHashMap

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1、hashMap和linkedHashMap和treeMap * LinkedHashMap是继承于HashMap，是基于HashMap和双向链表来实现的。 * HashMap无序；LinkedHashMap有序，可分为插入顺序和访问顺序两种。 * 如果是访问顺序，那put和get操作已存在的Entry时，都会把Entry移动到双向链表的表尾(其实是先删除再插入)。 * LinkedHashMap存取数据，还是跟HashMap一样使用的Entry[]的方式，双向链表只是为了保证顺序。 * LinkedHashMap是线程不安全的。　　hashMap示例 //无序 Map<String,String> hashMap = new HashMap<>(); hashMap.put("No1","小明1"); hashMap.put("No2","小明2"); hashMap.put("No3","小明3"); System.out.println("hashMap=>" + hashMap); linkedHashMap示例 // 有序，线程不安全，双向链表 // LinkedHashMap默认的构造参数是默认按照插入顺序的，就是说你插入的是什么顺序，读出来的就是什么顺序，但是也有访问顺序，就是说你访问了一个key，这个key就跑到了最后面 //

STL简介（Introduction to the Standard Template Library）

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昨天晚上花了一个晚上，翻译了一篇关于STL的文章。呵呵，第一次翻译这种东西，感觉计算机书籍还是英文原版的比较好，因为很多概念没法用中文恰当的表示（简直就是只可意会不可言传啊，:-)）。由于第一次翻译，呵呵，水平肯定比较菜了，关键是对STL以前没看过，比较陌生，所以翻译得很辛苦。还是看英文原版的好，翻译的太辛苦了。 STL简介（Introduction to the Standard Template Library） gshine 译 STL(标准模板库，Standard Template Library)，是一个包含容器（container）类，算法（algorithm）和迭代器（iterators）的C++类库。它提供了许多计算机科学方面的基本算法和数据结构。STL是一个泛型（generic）库，这意味着它的各个组件（components）都已经最大程度的参数化了，基本上STL里面的所有组件都是一个模板（template）。所以，在你使用STL之前，必须保证你已经理解了C++中模板（template）是如何工作的。容器和算法（container and algorithm）和大多数类库一样，STL也包含容器类—它的主要目的是容纳其他的对象（通常是多个）。这些容器类包括以下几个类（classes）：vector，list，deque，set，multiset，map

What are the main differences between a Rust Iterator and C++ Iterator? [closed]

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问题 Closed . This question needs to be more focused. It is not currently accepting answers. Want to improve this question? Update the question so it focuses on one problem only by editing this post. Closed 2 years ago . A typical example of a C++ iterator is a pointer, and can be used to point at an element in a C array like so: int array[] = {1, 2, 3, 4}; int* begin = std::begin(array); //Starting iterator int* end = std::end(array) //Ending iterator for(int* i = begin; i < end; i++) { std::cout

What are the main differences between a Rust Iterator and C++ Iterator? [closed]

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java软件开发人中经常误解区

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数组（array）转成集合（ ArrayList ）错误：如经常这样处理 List<String> list = Array.asList(arr); Arrays.asList()方法返回的是Arrays里的私有静态内部类ArrayList，不是集合java.util.ArrayList类。这是java.util.Arrays.Arrys.ArrayList类内部只有三个方法 set(),get(),contains(),但没有增加元素方法，因此他大小是不变的。要想创建一个集合ArrayList,这样的如： ArrayList<String> arrayList = new ArrayList<String>(Arrays.asList(arr)); 检查一个数组包含这个值（check if an Array contains a value）开发人员经常这样做： Set<String> set = new HashSet<String>(Arrays.asList(arr)); return set.contains(targetValue); 代码上多执行了几步，必需先转换成一个集合再给set; 可以这样写： Arrays.asList(arr).contains(targetValue); or for(String s:arr){if(s.equals

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