javascript - 如何引用字符串数组中的字符串？

Question

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Answer 1

遍历数组:

那是一个字符串数组，不要使用 for..in，使用普通的 for 循环:

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

正确使用for..in:

它用于对象的属性，例如:

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

for..in 对数组的副作用:

不要相信我的话，让我们看看为什么不使用它:数组中的 for..in 会产生副作用。看一看:

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!

See a demo fiddle for these codes.