How to find the maximum value of a number string in javascript

Javascript method to find the maximum value of a digital string: 1. Find the maximum and minimum values ​​of the js array through string splicing; 2. Use the sorting method to find the maximum and minimum values; 3. Find through the hypothesis method Maximum and minimum values; 4. Find the maximum value through the max and min methods of Math.

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

Four ways to find the maximum and minimum values ​​​​of js arrays

Given array [54,65,43,21,12,34, 45,58,97,24], find its maximum and minimum values?

Define array

var ary = [54,65,43,21,12,34,45,58,97,24];

1. String splicing method

Use toString and join to convert the array into a string, then splice it with the max and min methods of Math respectively, and finally execute the eval method

var maxN = eval("Math.max(" + ary.toString() + ")");
var minN = eval("Math.min(" + ary.toString() + ")");

or

var maxN = eval("Math.max(" + ary.join() + ")");
var minN = eval("Math.min(" + ary.join() + ")");

2. Sorting method

First sort the array from small to large. The first one in the array is the minimum value, and the last one is is the maximum value

ary.sort(function(a,b){return a-b;});
var minN = ary[0];
var maxN = ary[ary.length-1];

3. Assumption method

Assume that the first one in the array is the maximum (or minimum value), and compare it with the following values. If the latter values ​​are larger than the maximum If the value is larger (or smaller than the minimum value), replace the maximum value (or minimum value)

var maxN = ary[0];
var minN = ary[0];
for(var i=1;i<ary.length;i++){
  var cur = ary[i];
  cur>maxN ? maxN=cur : null;
  cur<minN ? minN=cur : null;
}

[Recommended learning: js basic tutorial]

4. The max and min methods of Math

Use the apply method to make the array available as a passed parameter

var maxN = Math.max.apply(null,ary);
var minN = Math.min.apply(null,ary);

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