Array.size（）VS Array.length [英] Array.size() vs Array.length

问题描述

两者有什么区别呢？

所以我知道 array.size（）是一个函数，而 array.length 是一个属性。是否有使用一个比其他一个用例？一个更有效的（我可以想象。长度是显著更快，因为它是一个属性而不是一个方法调用？）为什么人会使用较慢的选项？是否有某些浏览器不兼容的一个或其他？

  VAR X = [];
  的console.log（x.size（））;
  的console.log（x.length）;
  的console.log（x.size（）== x.length）;
  X = [1,2,3];
  的console.log（x.size（））;
  的console.log（x.length）;
  的console.log（x.size（）== x.length）;
 

将会打印：

  0，0，真
  3,3，真
 

解决方案

Array.size（）不是一个有效的方法

始终使用length属性

有一个图书馆或脚本添加尺寸方法对阵列原型，因为这不是本机阵列的方法。这是常见的做添加自定义的getter支持。如果你想获得的大小的数组（这是我能想到的唯一的事情是对这个名字很有用）的内存使用此的一个例子是，

Underscore.js不幸的是定义了一个尺寸实际上返回一个对象或数组的长度方法。由于不幸的是函数的长度属性被定义为命名参数的函数声明的数量，他们不得不使用替代和被选择的大小（计数会是一个更好的选择）。

What is the difference between the two?

So I know that array.size() is a function while array.length is a property. Is there a usecase for using one over the other? Is one more efficient (I would imagine .length to be significantly faster as it is a property rather then a method call?) Why would one ever use the slower option? Are there some browsers that are incompatible with one or the other?

  var x = [];
  console.log(x.size());
  console.log(x.length);
  console.log(x.size()==x.length);
  x =[1,2,3];
  console.log(x.size());
  console.log(x.length);
  console.log(x.size()==x.length);

Will print:

  0, 0, true
  3, 3, true

解决方案

Array.size() is not a valid method

Always use the length property

There is a library or script adding the size method to the array prototype since this is not a native array method. This is commonly done to add support for a custom getter. An example of using this would be when you want to get the size in memory of an array (which is the only thing I can think of that would be useful for this name).

Underscore.js unfortunately defines a size method which actually returns the length of an object or array. Since unfortunately the length property of a function is defined as the number of named arguments the function declares they had to use an alternative and size was chosen (count would have been a better choice).

这篇关于Array.size（）VS Array.length的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！