在 JavaScript 中压缩两个数组
JavaScript 有 map()
方法来压缩两个一定长度的数组。但是,如果相应的两个数组的长度不匹配,则最小加长数组将打印 undefined
作为其匹配项。
在这里,除了 map()
方法,我们将看到 Array.form()
方法和 Array.prototype.fill()
方法的演示,该方法明确声明了何时执行数组长度不匹配。
map()
函数接受一个回调函数,该函数将调用 x
数组元素并将它们与 y
数组的元素映射。这种简单的拉链方式也很容易掌握。
代码片段:
var x = [1,2,3];
var y = ["10", "20","30"];
var z = x.map(function(e, i) {
return [e, y[i]];
});
console.log(z);
输出:
在 Array.from()
方法的实例中,我们将有两个数组并将它们传递给箭头函数。该函数将首先匹配长度,然后映射来自两个不同数组的元素。此外,当发现任何元素丢失时,相应的地图将为此打印 undefined
。
代码片段:
var x = [1,2,3,4];
var y = ["10", "20", "30"];
var zip = (x, y) => Array.from(Array(Math.max(x.length, y.length)), (_, i) => [x[i], y[i]]);
console.log(zip(x,y));
输出:
Array.prototype.fill()
方法的工作方式与 Array.from()
方法类似,并按预期输出。
代码片段:
var x = [1,2,3];
var y = ["10", "20", "30", "40"];
const zip = (x, y) => Array(Math.max(x.length, y.length)).fill().map((_,i) => [x[i], y[i]]);
console.log(zip(x,y));
输出:
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