数组大小如何在Javascript中工作 [英] How do array sizes work in Javascript
问题描述
在JavaScript中,如果将数组设置为大小为5( var foo = new Array(5);
),这只是初始大小吗?可以在创建后扩展元素数量。是否有可能做这样的事情 - arr = new Array()
然后只是逐个分配元素?在此先感谢: - )
In JavaScript, if you set an array to be of size 5 ( var foo = new Array(5);
), is this just an initial size? Can you expand the number of elements after it is created. Is it possible to do something like this as well - arr = new Array()
and then just assign elements one by one? Thanks in advance :-)
推荐答案
是的,它只是一个初始大小,并不是必需的。如果你不使用一个数字,你可以立即填充。
Yes it is just an initial size, and it is not required. If you don't use a single number, you can immediately populate.
使用更简单的 [] $更常见c $ c>语法。
var arr = ['something', 34, 'hello'];
您可以使用括号设置(或替换)特定索引:
You can set (or replace) a specific index by using brackets:
arr[0] = "I'm here replacing whatever your first item was";
您可以使用push添加到最后:
You can add to the end by using push:
arr.push('add me');
如果您这样做,可能会在某些浏览器中获得更快的性能:
There may be faster performance in some browsers if you do it like this instead:
arr[arr.length] = 'add me';
您可以在任何索引处添加内容。
You can add something at any index.
您可以使用拼接完全删除项目:
You can remove an item completely using splice:
arr.splice(0, 1); // remove first item in the array (start at index 0, with 1 being removed)
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