Examples of Array Usage Analysis and array instance analysis in Javascript

Examples of Array Usage Analysis and array instance analysis in Javascript

This example describes how to use Array in Javascript. Share it with you for your reference. The specific analysis is as follows:

The Array object in JavaScript is an Array. It is a dynamic Array first, and a super complex such as "Array, List, HashMap/Dictionary" in C # and Java.

Array

Usage:

Example 1:

Var citys = new Array (); // create an Array object without initializing the length. Dynamic citys [0] = 'shanghai'; citys [1] = 'beijing '; citys [2] = 'shenzhen'; for (var I = 0; I <citys. length; I ++) {alert (citys [I]);}

Example 2 (recommended ):

Var arr = [10, true, 'Wow kakay']; for (var I = 0; I <arr. length; I ++) {alert (arr [I]);}

Forin traverses Array

Var arr = ['hani ', 'zhuang', 'manchu ', 'floaset']; for (var item in arr) {alert (item + '====' + arr [item]);}

Array key-value pairs

Usage

For example:

var arr=new Array(); arr["name"]='Jack'; arr["age"]=28; arr["gender"]='fale'; arr["height"]=180; for(var item in arr){   alert(item+'===='+arr[item]); }

Traverse Array key-value pairs

Forin Loop

var arr={name:'James',age:28}; for(var item in arr){   alert(item+'==='+arr[item]); }

Object. Key

var arr={name:'James',age:28}; alert(arr.name); alert(arr.age);

Pass Method Value

function f1(s){   alert(s.name);   alert(s.age); } f1({name:'Rose',age:20});

Special guy

Example 1:

var arr=[{name:'James',age:19},{name:'Rose',age:18},{name:'Max',age:20}]; for(var i=0;i<arr.length;i++){   alert(arr[i].name+'==='+arr[i].age); }

Example 2:

Var code = {name: 'max ', children: [{name: 'jack', age: 20}, {name: 'Rose', age: 18}]}; alert (code. name); for (var I = 0; I <code. children. length; I ++) {alert (code. children [I]. name + '>' + code. children [I]. age);} // Of course, forin can also be used, but for (var item in code. children) {alert (item + '>' + code. children [item]. name + '=' + code. children [item]. age );}

Array comparison

Customize a common comparison method

function max(arr,compare){   var m=arr[0];   for(var i=1;i<arr.length;i++){  if(compare(arr[i],m)){    m=arr[i];  }   }   return m; }var s1=max([12,32,33,100,8],function(n1,n2){   return n1>n2; }); alert(s1);var s2=max(["aa","bbbb","ccc"],function(n1,n2){   return n1.length>n2.length; });alert(s2);

Comparison Method sort () in Javascript ()

Example 1:

var arr=[23,12,56,200,45]; arr.sort(function(n1,n2){   return n1>n2; }); alert(arr);var arrStr=["aa","bbb","cccc"]; arrStr.sort(function(n1,n2){   return n1.length>n2.length; }); alert(arrStr);

Example 2:

var arr=[{name:'Bob',age:100},{name:'Tom',age:23},{name:'Rose',age:78}]; arr.sort(function(n1,n2){   return n1.age>n2.age; }); for(var i=0;i<arr.length;i++){   alert(arr[i].name);//Tom,Rose,Bob }

I hope this article will help you design javascript programs.