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Detailed explanation of JS objects and regular operator examples

小云云
Release： 2018-03-10 16:21:48
Original
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Array对象用于在单个变量中储存多个值，本文主要和大家分享Array对象用于在单个变量中储存多个值，希望能帮助到大家。

创建Array对象的语法

var arr1 = new Array(); // 创建空数组var arr2 = new Array(5); // 创建长度5 var arr3 = new Array(1,2,3,4,5); 
// 等价于var arr3 = new Array[1,2,3,4,5];var arr4 = new Array("5");// 等价于var arr4 = new Array["5"];
console.log(arr1,arr2,arr3,arr4);// 属性 length 数组的长度console.log(arr2.length);
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方法

push/pop
push/pop 对数组末尾添加/删除元素push():向数组的末尾添加一个或更多元素,并返回新的长度
var newLength = arr5.push(6,7,8);
console.log(arr5); //结果:[4,5,6,7,8]pop():删除并返回数组的最后一个元素
var num = arr5.pop();
console.log(arr5.length,num);// 结果:4,8
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unshift()/shift()
unshift():向数组的开头添加一个或更多元素,并返回新的长度
var b = arr5.unshift(1,2,3);
console.log(b); //结果:7shift():删除并返回数组的第一个元素
var c = arr5.shift();
console.log(c); //结果:1
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sort()
如果调用该方法时没有使用参数,将按字母顺序对数组中的元素进行排序,说的精确点,是按照字符编码的顺序进行排序.要实现这一点,首先应把数组的元素都换成字符串,以便进行比较
例1:<script type="text/javascript">
    var arr = new Array(6);
    arr[0] = "George";
    arr[1] = "John";
    arr[2] = "Thomas";
    arr[3] = "James";
    arr[4] = "Adrew";
    arr[5] = "Martin";

    console.log(arr);
    console.log(arr.sort());</script>结果:
George,John,Thomas,James,Adrew,Martin
Adrew,George,James,John,Martin,Thomas

例2:<script type="text/javascript">var arr = new Array(6);
arr[0] = "10";
arr[1] = "5";
arr[2] = "40";
arr[3] = "25";
arr[4] = "1000";
arr[5] = "1";

console.log(arr);
console.log(arr.sort());</script>结果:
10,5,40,25,1000,1
1,10,1000,25,40,5

例3:<script type="css/javascript">
    var arr = new Array(6);
    arr[0] = 10;
    arr[1] = 5;
    arr[2] = 40;
    arr[3] = 25;
    arr[4] = 1000;
    arr[5] = 1;

    console.log(arr);
    console.log(arr.sort())</script>结果:
10 5 40 25 1000 1
1 5 10 25 40 1000

如果要对上面的数进行倒序排列或者上面的数字都是字符串,然后根据数字大小进行排列,代码如下:

function sortNum(a,b){
    return a-b;
}
arr.sort(sortNum);

或者:
arr.sort(function(a,b){
    return a - b;
});
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splice
arrayObject.splice(index,howmany,item1,....,itemX);
说明:splice()方法可删除从index处开始的零个或者多个元素,并且用参数列表声明的一个或多个值来替换哪些被删除的元素,howmany的值与item的数量不需要一定保持一致.
如果从arrayObject中删除了元素,则返回的是含有被删除元素的数组.<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Document</title>
        <style type="text/css">
        </style>
    </head>
    <body>

    </body>
    <script type="text/javascript">
        var arr = new Array(5);
        arr[0] = "ds";
        arr[1] = "er";
        arr[2] = "ty";
        arr[3] = "uq";
        arr[4] = "yt";        var array = arr.splice(1,0,"qq","ww");
        console.log(array);
        console.log(arr);    </script> </html>结果:["ds", "qq", "ww", "er", "ty", "uq", "yt"]
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JavaScript Math对象

Math对象并不像Date和String那样是对象的类,因此没有构造函数Math(),像Math.sin()这样的函数只是函数,不是某个对象的方法.
你无需创建它,通过把Math作为对象使用就可以调用其所有属性和方法.
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<script type="text/javascript">
        // 取π的值
        var pi_value = Math.PI;
        console.log(pi_value);  // 结果:3.141592653589793
        // 求一个数的平方
        var sqrt_value = Math.sqrt(15);
        console.log(sqrt_value);  // 结果:3.872983346207417
        // 求一个数的绝对值
        var abs_value = Math.abs(-5);
        console.log(abs_value);  // 结果:5
        // 向上取整
        console.log(Math.ceil(5.1));  // 6
        console.log(Math.ceil(5.5));  // 6
        console.log(Math.ceil(5.9));  // 6
        console.log(Math.ceil(5));  // 5
        console.log(Math.ceil(-5.1));  // -5
        console.log(Math.ceil(-5.9));  // -5
        // 向下去整 floor(x)
        // 把数四舍五入为最接近的整数 Math.round(x)
        // Math.random() 返回0-1直接的随机数
    </script>
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JavaScript Date对象

<script type="text/javascript">
        var date1 = new Date("2016-9-1");        var date2 = new Date("2016-9-30");        // 两个日期相减得到的时间差,单位是毫秒
        var res = date2 - date1;
        console.log(res/1000/3600/24 + 1); //30
        // 从Date对象中,以四位数字返回年份
        var time = date1.getFullYear();
        console.log(time); //2016
        // 从Date对象中返回一个月中的某一天
        var d = date1.getDate();
        date1.setDate(d + 5);
        console.log(date1); //结果:Tue Sep 06 2016 00:00:00 GMT+0800 (CST)
        // 根据世界时，把 Date 对象转换为字符
        var date3 = new Date();
        console.log(date3);  //结果:Fri Mar 09 2018 20:19:46 GMT+0800 (CST)
        console.log(date3.toUTCString()); //结果:Fri, 09 Mar 2018 12:19:46 GMT
    </script>
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JavaScript String对象

<script type="text/javascript">
    // anchor()创建HTML锚
    var txt = "hello World";
    console.log(txt.anchor("text"));  // 结果:<a name="text">hello World</a>
    var str="Hello world!"
    console.log(str.length); //结果:12</script>
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正则运算符

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Document</title>
        <style type="text/css">
        </style>
    </head>
    <body>

    </body>
    <script type="text/javascript">
        // reg = /正则部分(定义的规则)/正则属性
        // g 全局匹配 加i 就不区分大小写
        var reg = /test/g;        var str = " hellotesthowareTestyoutest";
        console.log(str.match(reg)); // 结果:["test", "test"]
        var reg = /test/gi;
        console.log(str.match(reg)); //结果:["test", "Test", "test"]

        // \d代表数字
        var reg = /\d/g;        var str = "sdafsdgdf15dfbgsd566189safg4ag";
        console.log(str.match(reg)); //结果:["1", "5", "5", "6", "6", "1", "8", "9", "4"]

        // \w代表单词字符:数字 字母 下划线
        var reg = /\w/g;        var str = "dsf457__fgbd_1";
        console.log(str.match(reg)); // 结果:["d", "s", "f", "4", "5", "7", "_", "_", "f", "g", "b", "d", "_", "1"]

        // \.代表除去换行符的任意字符 (\n换行  \t 大空格 \b 退格符 \\代表是一个反斜杠)
        var reg4 = /./g;        var str4 = "\n\teH3_-=+_*/,.`() *&....%$#@!!^&\\";        //结果:[" ", "e", "H", "3", "_", "-", "=", "+", "_", "*", "/", ",", ".", "`", "(", ")", " ", "*", "&", ".", ".", ".", ".", "%", "$", "#", "@", "!", "!", "^", "&", "\"]
        console.log(str4.match(reg4));        //\s只要出现空白就匹配 \S只要不出现空白就匹配
        var reg5 = /\s/g;
        console.log(str4.match(reg5)); //结果: ["↵", "    ", " "]

        //var reg6 = /\w{6,12}/g; 可以作为用户名规则 6-12位
         var reg6 = /\d{2,3}/g;         var str6 = "3409800ru2h404";
         console.log(str6.match(reg6));          //小括号   代表 只匹配 括号中的元素.
         // var reg9 = /(34)|(32)/g
        // var reg9 = /3(4)|3(2)/g = var reg9 = /3[24]/g 他们是等价的
         var  reg9 = /3(4)|3(2)/g;         var str9 = "34876543323752677";
         console.log(str9.match(reg9));         //开头和结尾  只找第一位元素  如果找不到就回返回空
     var reg10 = /^34/g;     var str10 = "434349852342323";
     console.log(str10.match(reg10));     //开头和结尾  只找最后一位元素  如果找不到就回返回空
     var reg10 = /34$/g;     var str10 = "34349852342323";
     console.log(str10.match(reg10));     //开头和结尾  同时用就代表 只找括号中的元素.如果没有返回空.
     var reg10 = /^34$/g;     var str10 = "34";
     console.log(str10.match(reg10));     //限制字符串长度
     var reg10 = /^\d{11}$/g;     var str10 = "34349852342";
     console.log(str10.match(reg10));     // 匹配 3  到 6  长度的字符串 
     var reg10 = /^\d{3,6}$/g;     var str10 = "343498";
     console.log(str10.match(reg10));     //11位 纯数字的电话号码. 1开头 第二位是3-8 之间的数字.

     var reg11 = /^1(3[10379]|4[7]|5[0258]|6[1]|7[378]|8[029])\d{8}/g;     var str11 = "14755123198";
     console.log(str11.match(reg11));     //[a-z]所有的小写字母
     //[A-Z]所有的大写字母

     //邮箱
     //(4-10为单词字符 , 开头必须是字母)@
     //@qq @163. cn  com   
     //XXX@qq.com.cn

    </script></html>
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JS对象

JavaScript Array对象

Array对象用于在单个变量中储存多个值
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创建Array对象的语法

var arr1 = new Array(); // 创建空数组var arr2 = new Array(5); // 创建长度5 var arr3 = new Array(1,2,3,4,5); 
// 等价于var arr3 = new Array[1,2,3,4,5];var arr4 = new Array("5");// 等价于var arr4 = new Array["5"];
console.log(arr1,arr2,arr3,arr4);// 属性 length 数组的长度console.log(arr2.length);
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方法

push/pop
push/pop 对数组末尾添加/删除元素push():向数组的末尾添加一个或更多元素,并返回新的长度
var newLength = arr5.push(6,7,8);
console.log(arr5); //结果:[4,5,6,7,8]pop():删除并返回数组的最后一个元素
var num = arr5.pop();
console.log(arr5.length,num);// 结果:4,8
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unshift()/shift()
unshift():向数组的开头添加一个或更多元素,并返回新的长度
var b = arr5.unshift(1,2,3);
console.log(b); //结果:7shift():删除并返回数组的第一个元素
var c = arr5.shift();
console.log(c); //结果:1
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sort()
如果调用该方法时没有使用参数,将按字母顺序对数组中的元素进行排序,说的精确点,是按照字符编码的顺序进行排序.要实现这一点,首先应把数组的元素都换成字符串,以便进行比较
例1:<script type="text/javascript">
    var arr = new Array(6);
    arr[0] = "George";
    arr[1] = "John";
    arr[2] = "Thomas";
    arr[3] = "James";
    arr[4] = "Adrew";
    arr[5] = "Martin";

    console.log(arr);
    console.log(arr.sort());</script>结果:
George,John,Thomas,James,Adrew,Martin
Adrew,George,James,John,Martin,Thomas

例2:<script type="text/javascript">var arr = new Array(6);
arr[0] = "10";
arr[1] = "5";
arr[2] = "40";
arr[3] = "25";
arr[4] = "1000";
arr[5] = "1";

console.log(arr);
console.log(arr.sort());</script>结果:
10,5,40,25,1000,1
1,10,1000,25,40,5

例3:<script type="css/javascript">
    var arr = new Array(6);
    arr[0] = 10;
    arr[1] = 5;
    arr[2] = 40;
    arr[3] = 25;
    arr[4] = 1000;
    arr[5] = 1;

    console.log(arr);
    console.log(arr.sort())</script>结果:
10 5 40 25 1000 1
1 5 10 25 40 1000

如果要对上面的数进行倒序排列或者上面的数字都是字符串,然后根据数字大小进行排列,代码如下:

function sortNum(a,b){
    return a-b;
}
arr.sort(sortNum);

或者:
arr.sort(function(a,b){
    return a - b;
});
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splice
arrayObject.splice(index,howmany,item1,....,itemX);
说明:splice()方法可删除从index处开始的零个或者多个元素,并且用参数列表声明的一个或多个值来替换哪些被删除的元素,howmany的值与item的数量不需要一定保持一致.
如果从arrayObject中删除了元素,则返回的是含有被删除元素的数组.<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Document</title>
        <style type="text/css">
        </style>
    </head>
    <body>

    </body>
    <script type="text/javascript">
        var arr = new Array(5);
        arr[0] = "ds";
        arr[1] = "er";
        arr[2] = "ty";
        arr[3] = "uq";
        arr[4] = "yt";        var array = arr.splice(1,0,"qq","ww");
        console.log(array);
        console.log(arr);    </script> </html>结果:["ds", "qq", "ww", "er", "ty", "uq", "yt"]
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JavaScript Math对象

Math对象并不像Date和String那样是对象的类,因此没有构造函数Math(),像Math.sin()这样的函数只是函数,不是某个对象的方法.
你无需创建它,通过把Math作为对象使用就可以调用其所有属性和方法.
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<script type="text/javascript">
        // 取π的值
        var pi_value = Math.PI;
        console.log(pi_value);  // 结果:3.141592653589793
        // 求一个数的平方
        var sqrt_value = Math.sqrt(15);
        console.log(sqrt_value);  // 结果:3.872983346207417
        // 求一个数的绝对值
        var abs_value = Math.abs(-5);
        console.log(abs_value);  // 结果:5
        // 向上取整
        console.log(Math.ceil(5.1));  // 6
        console.log(Math.ceil(5.5));  // 6
        console.log(Math.ceil(5.9));  // 6
        console.log(Math.ceil(5));  // 5
        console.log(Math.ceil(-5.1));  // -5
        console.log(Math.ceil(-5.9));  // -5
        // 向下去整 floor(x)
        // 把数四舍五入为最接近的整数 Math.round(x)
        // Math.random() 返回0-1直接的随机数
    </script>
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JavaScript Date对象

<script type="text/javascript">
        var date1 = new Date("2016-9-1");        var date2 = new Date("2016-9-30");        // 两个日期相减得到的时间差,单位是毫秒
        var res = date2 - date1;
        console.log(res/1000/3600/24 + 1); //30
        // 从Date对象中,以四位数字返回年份
        var time = date1.getFullYear();
        console.log(time); //2016
        // 从Date对象中返回一个月中的某一天
        var d = date1.getDate();
        date1.setDate(d + 5);
        console.log(date1); //结果:Tue Sep 06 2016 00:00:00 GMT+0800 (CST)
        // 根据世界时，把 Date 对象转换为字符
        var date3 = new Date();
        console.log(date3);  //结果:Fri Mar 09 2018 20:19:46 GMT+0800 (CST)
        console.log(date3.toUTCString()); //结果:Fri, 09 Mar 2018 12:19:46 GMT
    </script>
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JavaScript String对象

<script type="text/javascript">
    // anchor()创建HTML锚
    var txt = "hello World";
    console.log(txt.anchor("text"));  // 结果:<a name="text">hello World</a>
    var str="Hello world!"
    console.log(str.length); //结果:12</script>
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正则运算符

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Document</title>
        <style type="text/css">
        </style>
    </head>
    <body>

    </body>
    <script type="text/javascript">
        // reg = /正则部分(定义的规则)/正则属性
        // g 全局匹配 加i 就不区分大小写
        var reg = /test/g;        var str = " hellotesthowareTestyoutest";
        console.log(str.match(reg)); // 结果:["test", "test"]
        var reg = /test/gi;
        console.log(str.match(reg)); //结果:["test", "Test", "test"]

        // \d代表数字
        var reg = /\d/g;        var str = "sdafsdgdf15dfbgsd566189safg4ag";
        console.log(str.match(reg)); //结果:["1", "5", "5", "6", "6", "1", "8", "9", "4"]

        // \w代表单词字符:数字 字母 下划线
        var reg = /\w/g;        var str = "dsf457__fgbd_1";
        console.log(str.match(reg)); // 结果:["d", "s", "f", "4", "5", "7", "_", "_", "f", "g", "b", "d", "_", "1"]

        // \.代表除去换行符的任意字符 (\n换行  \t 大空格 \b 退格符 \\代表是一个反斜杠)
        var reg4 = /./g;        var str4 = "\n\teH3_-=+_*/,.`() *&....%$#@!!^&\\";        //结果:[" ", "e", "H", "3", "_", "-", "=", "+", "_", "*", "/", ",", ".", "`", "(", ")", " ", "*", "&", ".", ".", ".", ".", "%", "$", "#", "@", "!", "!", "^", "&", "\"]
        console.log(str4.match(reg4));        //\s只要出现空白就匹配 \S只要不出现空白就匹配
        var reg5 = /\s/g;
        console.log(str4.match(reg5)); //结果: ["↵", "    ", " "]

        //var reg6 = /\w{6,12}/g; 可以作为用户名规则 6-12位
         var reg6 = /\d{2,3}/g;         var str6 = "3409800ru2h404";
         console.log(str6.match(reg6));          //小括号   代表 只匹配 括号中的元素.
         // var reg9 = /(34)|(32)/g
        // var reg9 = /3(4)|3(2)/g = var reg9 = /3[24]/g 他们是等价的
         var  reg9 = /3(4)|3(2)/g;         var str9 = "34876543323752677";
         console.log(str9.match(reg9));         //开头和结尾  只找第一位元素  如果找不到就回返回空
     var reg10 = /^34/g;     var str10 = "434349852342323";
     console.log(str10.match(reg10));     //开头和结尾  只找最后一位元素  如果找不到就回返回空
     var reg10 = /34$/g;     var str10 = "34349852342323";
     console.log(str10.match(reg10));     //开头和结尾  同时用就代表 只找括号中的元素.如果没有返回空.
     var reg10 = /^34$/g;     var str10 = "34";
     console.log(str10.match(reg10));     //限制字符串长度
     var reg10 = /^\d{11}$/g;     var str10 = "34349852342";
     console.log(str10.match(reg10));     // 匹配 3  到 6  长度的字符串 
     var reg10 = /^\d{3,6}$/g;     var str10 = "343498";
     console.log(str10.match(reg10));     //11位 纯数字的电话号码. 1开头 第二位是3-8 之间的数字.

     var reg11 = /^1(3[10379]|4[7]|5[0258]|6[1]|7[378]|8[029])\d{8}/g;     var str11 = "14755123198";
     console.log(str11.match(reg11));     //[a-z]所有的小写字母
     //[A-Z]所有的大写字母

     //邮箱
     //(4-10为单词字符 , 开头必须是字母)@
     //@qq @163. cn  com   
     //XXX@qq.com.cn

    </script></html>
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相关推荐：

多种创建js对象的方法详细讲述

js对象实例详解(JavaScript对象深度剖析,深度理解js对象)

JavaScript对象深度剖析以及深度理解js对象的实例分享

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