在JavaScript中从一个阵列中添加一个项目到另一个在比较两个数组 [英] comparing two arrays before adding an item from one array to another in JavaScript

问题描述

我有两个数组。

  VAR addFrom = [橙色，香蕉，西瓜，柠檬，桃花];
VAR AddTo就= [鸭梨，橘子，葡萄，橙色，蓝莓];
 

我想检查一下addFrom数组的第一个项目已经处于AddTo就数组。

如果在AddTo就数组不具有addFrom数组的第一个项目，我想推动此项目为AddTo就数组。

但是，如果addFrom数组中的第一项已经是AddTo就阵中，我想移动到第二项addFrom阵列中做同样的事情，直到我找到该项目在addFrom数组，它是不是AddTo就数组，然后将被推向AddTo就数组中为止。我想只有一个项目添加到AddTo就数组。

因此​​，我希望AddTo就数组是这样的：

  VAR AddTo就= [鸭梨，橘子，葡萄，橙色，蓝莓，香蕉];
 

我怎样才能做到这一点在JavaScript中？

解决方案

您可以使用的 阵列＃一些（） 并停止迭代，如果一个项目是不是在 AddTo就阵列。

\r

\r

VAR addFrom = [橙色，香蕉，西瓜，柠檬，桃花]，\r
    AddTo就= [鸭梨，橘子，葡萄，橙色，蓝莓];\r
\r
addFrom.some（函数（）{\r
    如果（！〜addTo.indexOf（一））{\r
        addTo.push（一）;\r
        返回true;\r
    }\r
}）;\r
\r
的document.write（'＆LT; pre＆GT;'+ JSON.stringify（AddTo就，0,4）+'＆LT; / pre＆GT;'）;

\r

\r

\r

I have two arrays.

var addFrom = ["orange", "banana", "watermelon", "lemon", "peach"];
var addTo = ["pear", "tangerine", "grape", "orange", "blueberry"];

I would like to check if the first item in "addFrom" array is already in "addTo" array.

If the "addTo" array does not have the first item in "addFrom" array, I would like to push this item to "addTo" array.

However, if the first item in the "addFrom" array is already in the "addTo" array, I would like to move on to the second item in the "addFrom" array and do the same thing until I find the item in the "addFrom" array that is not in the "addTo" array, which will then be pushed to the "addTo" array. and I want to add only one item to the "addTo" array.

As a result, I want the "addTo" array to look like this:

var addTo = ["pear", "tangerine", "grape", "orange", "blueberry", "banana"];

How can I do this in JavaScript?

解决方案

You could use Array#some() and stop the iteration if one item is not in the addTo array.

var addFrom = ["orange", "banana", "watermelon", "lemon", "peach"],
    addTo = ["pear", "tangerine", "grape", "orange", "blueberry"];

addFrom.some(function (a) {
    if (!~addTo.indexOf(a)) {
        addTo.push(a);
        return true;
    }
});

document.write('<pre> ' + JSON.stringify(addTo, 0, 4) + '</pre>');

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