Question

This question already has answers here:

How to sort an array of integers correctly (32 answers)

Closed 7 years ago.

如下:

<script type="text/javascript">

function sortNumber(a,b) {
  return a - b;
}

var n = ["10", "5", "40", "25", "100", "1"];
document.write(n.sort(sortNumber));

</script>

<代码>sortNumber用于分类编号吗? 是什么意思,为什么存在? 为什么sortNumber in n.sort(sortNumber)n t 具体指明了a和b的任何参数?

Answer 1

The JavaScript sort() function may or may not take a parameter.
The parameter would be a function - meaning what function is to be used to assess which of two elements should be before the other.

The n array is made of strings representing numbers.
Doing a simple sort() without a function, an alphabetical order would be used: the result would be

 "1", "10", "25"... "5"

并且不正确。

提供一种功能,sortNumber, 计票sort,每次<代码>sort<>/code>想要知道这两个项目中哪些是摆在另一个项目面前时,即以两个阵列要素标明该功能。

因此,sortNumber 提供了两个项目,即:<代码>数字操作,以换取

a negative value, meaning a is before b
a positive value, b is before a
zero: they re equal in terms of order (order doesn t matter).

Answer 2

您需要考虑一下<代码>sort()的消耗量;sort(>的消费功能,其中界定了“der”。简化:

array.sort(sortfunc)

因此,当你确定职能类别时,你实际上正在确定如何分类。

因此,如果我们确定一个机构被定义为:

return a - b;

我们正在要求通过 as令进行分类。

如果我们用身体确定职能:

return b - a;

我们正在要求以降临秩序为平地。

Hope this helps

Answer 3

When you write n.sort(sortNumber), you re passing the sortNumber function to sort.
You aren t calling the sortNumber function, so you don t pass any parameters.

Javascript s sort method takes an optional parameter: a function that compares two elements.
sort will call the function you pass to compare pairs of elements in the array.
The compare function that you supply should take two parameters and return a number indicating which one is bigger.

Answer 4

这种职能接受2项论点,即<代码>a和b,并本应退还若干项。

if a is more than b then it should return any positive number.
if a is less than b then it should return any negative number.
if a is equals to b then it should return 0.

。也可使用<条码>b-<条码>取而代之。你们有这个想法。

友情链接