javascript 不使用concat方法添加两个数组
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原文地址: http://stackoverflow.com/questions/5240335/
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Add two arrays without using the concat method
提问by qw3n
Here is a sample of what I would like to do
这是我想做的示例
function test(r){
var arr = ['d','e','f'];
r.push(arr);
/*
More Code
*/
return r;
}
var result = test(['a','b','c']);
alert(result.length);//I want this to alert 6
What I need to do is pass in an array and attach other arrays to the end of it and then return the array. Because of passing by reference I cannot use array.concat(array2);. Is there a way to do this without using something like a for loop to add the elements one by one. I tried something like r.push(arr.join());but that did not work either. Also, I would like the option of having objects in the arrays so really the r.push(arr.join());doesn't work very well.
我需要做的是传入一个数组并将其他数组附加到它的末尾，然后返回该数组。由于通过引用传递，我无法使用array.concat(array2);. 有没有办法在不使用 for 循环之类的东西一个一个地添加元素的情况下做到这一点。我试过类似的东西，r.push(arr.join());但也没有奏效。另外，我想要在数组中包含对象的选项，因此实际上r.push(arr.join());效果不佳。
回答by emulbreh
>>> var x = [1, 2, 3], y = [4, 5, 6];
>>> x.push.apply(x, y) // or Array.prototype.push.apply(x, y)
>>> x
[1, 2, 3, 4, 5, 6]
Alternatively using destructuringyou can now do this
或者使用解构，你现在可以做到这一点
//generate a new array
a=[...x,...y];
//or modify one of the original arrays
x.push(...y);
回答by mVChr
function test(r){
var _r = r.slice(0), // copy to new array reference
arr = ['d','e','f'];
_r = _r.concat(arr); // can use concat now
return _r;
}
var result = test(['a','b','c']);
alert(result.length); // 6
回答by meouw
This is emulbreh's answer, I'm just posting the test I did to verify it. All credit should go to emulbreh
这是emulbreh 的回答，我只是发布了我为验证所做的测试。所有的功劳都应该归功于 emulbreh
// original array
var r = ['a','b','c'];
function test(r){
var arr = ['d','e','f'];
r.push.apply(r, arr);
/*
More Code
*/
return r;
}
var result = test( r );
console.log( r ); // ["a", "b", "c", "d", "e", "f"]
console.log( result === r ); // the returned array IS the original array but modified
