Tersest在JavaScript中从1..20创建一个整数数组的方式 [英] Tersest way to create an array of integers from 1..20 in JavaScript

问题描述

什么是创建这个数组的tersest方式：

What would be the tersest way to create this array:

var x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
         11, 12, 13, 14, 15, 16, 17, 18, 19, 20];

例如，一个为循环：

var x = [];
for (var i=1;i<=20;i++) {
  x.push(i);
}

或，而循环：

var x = [], i = 1, endInt = 20;
while (i <= endInt) {
  x.push(i);
  i++;
}

会不会有其他的例子，这将是更简洁 - 换句话说 - 少code？我想的东西像红宝石，其中相当于code，我相信会是那样简单 1..20 。我不知道这样的JavaScript语法，但我不知道是否有更短的方式做同样的事情。

Would there be other examples that would be terser -- in other words -- less code? I'm thinking of things like in Ruby where the equivalent code I believe would be as simple as 1..20. I'm not aware of syntax like that in JavaScript but I'm wondering if there are shorter ways to do that same thing.

更新：我并没有考虑删除分号或 VAR 寻找答案的问题，但我不得不承认这个问题意味着， 。我比较好奇的算法比剃须字节。很抱歉，如果我不清楚！此外，使它成为一个功能非常简单，只需一巴掌的功能范围（起始，结束）{/ *胆量在这里* /} 周围和你的存在。现在的问题是是否有新的方法，以胆。

UPDATE: I wasn't thinking of removing semicolons or var for answers in the question, but I have to admit the question implies that. I am more curious about algorithms than shaving bytes. Sorry if I was unclear! Also, making it into a function is simple enough, just slap function range(start, end) { /* guts here */ } around it and you're there. The question is are there novel approaches to the "guts."

推荐答案

想有点后，这是最短的执行标准范围（N）功能在JavaScript我能想出：

After thinking about it a bit, this is the shortest implementation of the standard range(N) function in JavaScript I could come up with:

function range1(i){return i?range1(i-1).concat(i):[]}

的注意：不要在生产中使用这一点;它的O（N ^ 2）的

Note: Do not use this in production; it's O(N^2)

对比与目前顶级投回答：

Contrast with current top-voted answer:

function range1(i){var x=[];var i=1;while(x.push(i++)<i){};return x}

---

例如：

---

Example:

> range1(5)
[1, 2, 3, 4, 5]

---

这是像典范递归，但我希望它会更长，直到我认为三元if语句，它把它降低到42需要的字符。

---

This is like the poster child for recursion, though I was expecting it to be longer until I thought of ternary-if-statement, which brings it down to 42 necessary characters.

请注意，标准范围函数返回[开始，结束）可以写做 .concat（I-1）。

Note that the "standard" range function returning [start,end) can be written by doing .concat(i-1).

更新：哦，我被滥用的循环发现了一个令人难以置信的短版丑陋强制性语法，反向排序，事实上，分配返回值：的（Y = []，I = 20 ; Y [ - 我] =我;）{} 仅由25个字符（虽然你会希望 VAR是，你可以插入一个for循环，和+1如果你不想0 ... 19）。虽然不短，如果你需要定义一个函数，它比短 I R（I-1）.concat（I）：[] 如果不这样做需要进行功能

Update: Ooh, I discovered an incredibly short version with ugly imperative syntax by abusing for loops, reverse-ordering, the fact that assignments return a value: for(y=[],i=20;y[--i]=i;){} consisting of only 25 characters (though you will want var y which you can insert into a for loop, and +1 if you don't want 0...19). While it is not shorter if you need to define a function, it is shorter than i?r(i-1).concat(i):[] if you do not need to make a function.

更新Sep13,2015：

Update Sep13,2015:

刚刚想出了这个它与支持ES6标准的浏览器的工作原理新方法：

Just came up with this new method which works with browsers which support the ES6 standard:

> Array(5).fill().map((x,i)=>i)
[0, 1, 2, 3, 4]

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