我如何引用字符串数组中的字符串？ [英] How do I reference the string in a array of strings?

问题描述

我有以下内容：

var tags = ["Favorite", "Starred", "High Rated"];

for (var tag in tags) {
    console.log(tag);
}

输出为

0
1
2

我想它想的输出：

I'd like it to output:

Favorite
Starred
High Rated

我如何做到这一点？谢谢你。

How do I do this? Thanks.

推荐答案

这是一个字符串数组，不要使用的for..in ，使用香草为循环：

Itearting over an array:

That's an array of strings, don't use for..in, use the vanilla for loop:

var tags = ["Favorite", "Starred", "High Rated"];
for (var i = 0; i < tags.length; i++) { // proper way to iterate an array
    console.log(tags[i]);
}

输出：

Favorite
Starred
High Rated

的正确用法的for..in ：

这是为对象的属性，如：

Proper usage of for..in:

It is meant for object's properties, like:

var tags2 = {"Favorite": "some", "Starred": "stuff", "High Rated": "here"};
for (var tag in tags2) { // enumerating objects properties
    console.log("My property: " + tag +"'s value is " +tags2[tag]);
}

输出：

My property: Favorite's value is some
My property: Starred's value is stuff
My property: High Rated's value is here

的副作用的for..in 使用数组：

不要把我的话，让我们来看看为什么不使用它：的for..in 在数组中可能有副作用。请看下图：

Side effects of for..in with arrays:

Don't take my word for it, let's see why not use it: for..in in arrays can have side effects. Take a look:

var tags3 = ["Favorite", "Starred", "High Rated"];
tags3.gotcha = 'GOTCHA!'; // not an item of the array

// they can be set globally too, affecting all arrays without you noticing:
Array.prototype.otherGotcha = "GLOBAL!";

for (var tag in tags3) {
    console.log("Side effect: "+ tags3[tag]);
}

输出：

Side effect: Favorite
Side effect: Starred
Side effect: High
Side effect: GOTCHA!
Side effect: GLOBAL!

查看这些codeS演示小提琴。

See a demo fiddle for these codes.

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