TypeScript 中的哈希集
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/40180641/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Hashset in TypeScript
提问by angryip
I am attempting to do something very basic in TypeScript. Get a list of unique strings while parsing a map as referenced in this post.
我正在尝试在 TypeScript 中做一些非常基本的事情。在解析本文中引用的地图时获取唯一字符串列表。
Here is what I am attempting to do:
这是我正在尝试做的事情：
let myData = new Array<string>();
for (let myObj of this.getAllData()) {
let name = myObj.name;
console.log("## we have " + name);
console.log("### is property ? " + myData.hasOwnProperty(name));
if (!myData.hasOwnProperty(name)){
myData.push(name);
}
}
My printout will always evaluate to false for any string, duplicate or not. Here is some sample output:
对于任何字符串，无论是否重复，我的打印输出将始终评估为 false。这是一些示例输出：
## we have COW
### is property ? false
## we have COW
### is property ? false
## we have RAODN
### is property ? false
## we have COOL
### is property ? false
However, when the process completes, my list contain duplicates. I have tried looking at this documentation, but there is no mention of a 'hashset' or any set in general.
但是，当该过程完成时，我的列表包含重复项。我曾尝试查看此文档，但总体上没有提及“哈希集”或任何集。
Is there something equivalent in TypeScript of a Set? i.e A list of unique elements
Set 的 TypeScript 中是否有等价的东西？即唯一元素列表
回答by Marcel
It exists!
它存在！
mySet: Set<string> = new Set<string>();
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set
回答by Jesse Palmer
The title of this post asks for a HashSet. The Set JavaScript implementation loops over each element in the Set, which would be O(n). For a data structure to be a HashSet, it should be close to O(1). If you are interested in a HashSet, it's pretty easy to create it in TypeScript. Here is a basic implementation:
这篇文章的标题要求一个 HashSet。Set JavaScript 实现循环遍历 Set 中的每个元素，这将是 O(n)。对于要成为 HashSet 的数据结构，它应该接近 O(1)。如果您对 HashSet 感兴趣，在 TypeScript 中创建它非常容易。这是一个基本的实现：
class HashSet {
private values = {}
add(val) {
this.values[val] = true
}
has(val) {
return this.values[val] === true
}
remove(val) {
delete this.values[val]
}
getValues() {
return Object.keys(this.values)
}
}
const hashSet = new HashSet()
hashSet.add(5)
hashSet.add(10)
console.log(hashSet.has(5)) // true
console.log(hashSet.getValues()) // [5, 10]
hashSet.remove(5)
console.log(hashSet.has(5)) // false
回答by silentsod
An object {} is a key value pair dictionary is a hash set in JavaScript which TypeScript is a superset of and therefore you can use a JS object to serve in this role.
对象 {} 是键值对字典是 JavaScript 中的哈希集，TypeScript 是其超集，因此您可以使用 JS 对象来充当此角色。
A quick version from the code you posted:
您发布的代码的快速版本：
let myData = {};
for (let myObj of this.getAllData()) {
let name = myObj.name;
if (!myData[name]){
myData[name] = name;
}
}
回答by angryip
I found my own solution with something like this:
我找到了自己的解决方案，如下所示：
let myData = new Array<string>();
for (let myObj of this.getAllData()) {
let name = myObj.name;
if (myData.indexOf(name) == -1){
myData.push(name);
}
}
Not sure that it is a better solution than any so far, but it is something I have decided to stick with until a better one is chosen.
不确定它是否比迄今为止的任何解决方案都更好，但我决定坚持使用它，直到选择更好的解决方案为止。
