javascript正则表达式

/*
//复习
var obj= new Number(2);
alert(Number.MIN_VALUE);

var num = new Number(22e3);
alert(num);
alert(isFinite(num));//判断是否超出了规定的范围


var person={fname:"John",lname:"Doe",age:25};
var txt="";
for (x in person)
  {
  txt=txt + person[x];
 
  }
  alert(txt); 
------------------------------------------

正则表达式(regular expression)
创建方式：
1.使用new运算符
var reg = new RegExp("box");
alert(reg);//return /box/

var reg = new RegExp("box","ig");//模式修饰符的可选参数 ： i-忽略大小写；g-全局匹配；m-多行匹配。
alert(reg);//return /box/gi

2.使用字面量方式创建
var reg = /box/;
alert(reg);//return /box/


var reg = /box/ig;
alert(reg);//return /box/gi
---------------------------

var pattern = new RegExp("Box");
var str = new String("box");
alert(pattern.test(str));//return false

var pattern = new RegExp("Box","i");
var str = new String("This is a box");
alert(pattern.test(str));//return true

alert(/Box/.test("This is a box!"));//false


alert(/Box/i.test("This is a box!"));//true

alert(/Box/.exec("This is a box!"));//return null
alert(/Box/i.exec("This is a box!"));//return box 

alert(/Box/i.exec("This box is a Box!"));//return box
alert(/Box/i.exec("This Box is a box!")); //return Box
alert(/Box/ig.exec("This box is a Box!"));//return box


var pattern = new RegExp("Box","i");
var str = new String("This is a Box! That box is a Box!");
var result = pattern.exec(str);
var result2 = str.match(pattern);//String对象的方法
alert(typeof result2);
alert(result2[0]);


var pattern = new RegExp("Box","ig");//全局匹配，即找到所有匹配项目
var str = new String("This box is a Box! That box is a Box!");
var result = pattern.exec(str);//返回第一个匹配的字符串
alert(result[1]);//return undefined 证明返回的不是数组
var result2 = str.match(pattern);//String对象的方法
alert(typeof result2);
alert(result2[1]);//return box证明返回的是一个数组


var pattern = new RegExp("Box","i");
var str = new String("This box is a Box! That box is a Box!");
var result = str.search(pattern);//String对象的方法
alert(result);//return 5   返回第一个匹配的位置,找不到就返回-1


var pattern = new RegExp("Box","i");//没有开启全局
var str = new String("This box is a Box! That box is a Box!");
var result = str.replace(pattern,"Tom");
alert(result);//This Tom is a Box! That box is a Box!


var pattern = new RegExp("Box","ig");//开启全局
var str = new String("This box is a Box! That box is a Box!");
var result = str.replace(pattern,"Tom");
alert(result);//This Tom is a Tom! That Tom is a Tom!
var pattern = new RegExp("!","ig");//开启全局
var str = new String("This box is a Box! That box is a Box!");
var result = str.split(pattern);
alert(result);//This box is a Box, That box is a Box,

var pattern = new RegExp("!","ig");//开启全局
var str = new String("This box is a Box! That box is a Box!");
var result = str.split(pattern);
for(var i=0;i<result.length;i++){
alert(result[i]);
}

var pattern = new RegExp("!","ig");//开启全局
var str = new String("This box is a Box! That box is a Box!");
var result = str.split(pattern);
for(rs in result){
alert(rs);//return 0, return 1, return 2
}

var pattern = new RegExp("Box","ig");//开启全局
var str = new String("This box is a Box! That box is a Box!");
var result = pattern.test(str);
//alert(RegExp.input);//This box is a Box! That box is a Box!
alert(RegExp.leftContext);
alert(RegExp.rightContext);
alert(RegExp.lastMatch);


var pattern = /g..gle/; //.表示除了换行符以外的其他任意字符
var str = "google";
alert(pattern.test(str));//true


var pattern = /go*gle/; //o*表示0到多个o
var str = "gooogle";
alert(pattern.test(str));//true

var pattern = /go+gle/; //o+表示1到多个o
var str = "gooogle";
alert(pattern.test(str));//true

var pattern = /go?gle/; //o?表示0个，或者1个
var str = "ggle";
alert(pattern.test(str));//true

var pattern = /go{2,4}gle/; //o{2,4}表示2~4个o，包含2和4
var str = "google";
alert(pattern.test(str));//true

var pattern = /go{2}gle/; //o{2}表示只出现2个o
var str = "google";
alert(pattern.test(str));//true


var pattern = /go{2,}gle/; //o{2,}表示o出现2个或者2个以上
var str = "gooogle";
alert(pattern.test(str));//true

var pattern = /go[a-z]gle/; //[a-z]表示26个小写字母中的任意一个
var str = "google";
alert(pattern.test(str));//true

var pattern = /go[0-9]gle/; //[0-9]表示0~9中的任意一个
var str = "go8gle";
alert(pattern.test(str));//true

var pattern = /go[a-zA-Z0-9]gle/; //[a-zA-Z0-9]是一种复合写法，表示26个大小写字母或数字中的任意一个
var str = "go8gle";
alert(pattern.test(str));//true

var pattern = /go[^0-9]gle/; //[^0-9]表示非0~9中的任意一个字符
var str = "go8gle";
alert(pattern.test(str));//false

var pattern = /^go[0-9]gle/; //^表示从头开始匹配
var str = "ggo8gle";
alert(pattern.test(str));//false

var pattern = /go\wgle/; //\w表示任意一个字母，数字或下划线，等同于[a-zA-Z0-9_]
var str = "go_gle";
alert(pattern.test(str));//true

var pattern = /go\Wgle/; //\w表示任意一个非字母，非数字且非下划线的字符，等同于[^a-zA-Z0-9_]
var str = "go_gle";
alert(pattern.test(str));//false

var pattern = /go\dgle/; //\d表示任意一个数字，等同于[0-9]
var str = "go9gle";
alert(pattern.test(str));//true

var pattern = /go\Dgle/; //\D表示任意一个非数字的字符，等同于[^0-9]
var str = "go9gle";
alert(pattern.test(str));//false

var pattern = /google$/; //$表示从行尾开始匹配
var str = "ggoogle";
alert(pattern.test(str));//true

var pattern = /goo\sgle/; //\s查找空白字符。
var str = "ggoo gle";
alert(pattern.test(str));//true

var pattern = /google\b/; //\b匹配单词边界。类似于$
var str = "ggoogle";
alert(pattern.test(str));//true

var pattern = /google|baidu|bing/; //竖线|表示匹配或选择模式
var str = "ggoogle";
alert(pattern.test(str));//true

var pattern = /(google|baidu|bing)s/; //竖线|表示匹配或选择模式
var str = "ggoogles";
alert(pattern.test(str));//true


var pattern = /google{4,8}$/; //表示结尾处e出现4~8次
var str = "ggoogleeee";
alert(pattern.test(str));//true


var pattern = /(google){4,8}$/; //括号表示分组，表示结尾处google出现4~8次
var str = "ggooglegooglegooglegoogle";
alert(pattern.test(str));//true

var pattern = /8(.*)8/; //分组
var str = "goo8google8gle";
//pattern.test(str);
//pattern.exec(str);
str.match(pattern);
alert(RegExp.$1);//google    RegExp.$1表示获取模式中第一个分组对应的匹配字符串  

var pattern = /8(.*)8/; //分组
var str = "this is 8google8";
document.write(str.replace(pattern,"<strong>google</strong>"));

var pattern = /8(.*)8/; //分组
var str = "this is 8google8";
document.write(str.replace(pattern,"<strong>$1</strong>"));

var pattern = /8(.*)8/; //分组
var str = "this is 8google8";
document.write(str.replace(pattern,"<strong>$1</strong>"));



var pattern = /[a-z]/; 
var str = "you love";
alert(str.replace(pattern,"1"));//1ou love

var pattern = /[a-z]+/; //+贪婪模式
var str = "you love";
alert(str.replace(pattern,"1"));//1 love

var pattern = /[a-z]+?/; //使用+?惰性模式
var str = "you love";
alert(str.replace(pattern,"1"));//1ou love

var pattern = /8(.*)8/; //使用了贪婪模式
var str = "this is 8google8 8google8 8google8 ";
document.write(str.replace(pattern,"<strong>$1</strong>"));//this is <strong>google8 8google8 8google</strong>


var pattern = /8(.*?)8/; //使用了惰性模式
var str = "this is 8google8 8google8 8google8 ";
document.write(str.replace(pattern,"<strong>$1</strong>"));//this is <strong>google</strong> 8google8 8google8 


var pattern = /8(.*?)8/g; //使用了惰性模式，开启全局
var str = "this is 8google8 8google8 8google8 ";
document.write(str.replace(pattern,"<strong>$1</strong>"));//this is <strong>google</strong><strong>google</strong><strong>google</strong>


var pattern = /8([^8]*)8/g; //另一种惰性，屏蔽了8的匹配，开启全局
var str = "this is 8google8 8google8 8google8 ";
document.write(str.replace(pattern,"<strong>$1</strong>"));//this is <strong>google</strong><strong>google</strong><strong>google</strong>

var pattern = /8([^8]*)8/g; //另一种惰性，屏蔽了8的匹配，开启全局
var str = "this is 8google8 8google8 8google8 ";
document.write(str.replace(pattern,"<strong>$1</strong>"));//this is <strong>google</strong><strong>google</strong><strong>google</strong>



var pattern=/(\d+)([a-z])/; //捕获型分组，所有的分组都捕获返回
var str="123abc";
var a=pattern.exec(str);
alert(a[0]);//123a  返回匹配到的字符串
alert(a[1]);//123  返回第一个分组匹配到的字符串
alert(a[2]);//a  返回第二个分组匹配到的字符串

var pattern=/(\d+)(?:[a-z])/; //非捕获型分组，只需在不需要捕获返回的分组加上?:
var str="123abc";
var a=pattern.exec(str);
alert(a[0]);//123a  返回匹配到的字符串
alert(a[1]);//123  返回第一个分组匹配到的字符串
alert(a[2]);//undefined  返回第二个分组匹配到的字符串

console.log("test zhangweiwen");



var pattern=/(a?(b?(c?)))/;//嵌套匹配，从外到内
var str="abc";
alert(pattern.exec(str));//abc,abc,bc,c


var pattern=/goo(?=gle)/;//必须是后面跟着gle，才能返回goo
var str="google";
alert(pattern.exec(str));//goo


var pattern=/[1-9][0-9]{5}/;
var str="741027";//必须是6位，必须为数字，首位不能为0
alert(pattern.test(str));
alert(str.match(pattern));

var pattern=/^\w*\.zip|7z&/;  //字母，数字，下划线为压缩文件的名 
var str="study_2015.zip";
alert(pattern.test(str));
var pattern=/(\s+)/g;


var str="        goog      le     ";
alert(str.replace(pattern,","));
//alert("|"+pattern.exec(str)+"|");
alert(str.match(pattern));

var pattern=/(\w+)/g;
var str="        goog      le     a";
alert(str.replace(pattern,","));
//alert("|"+pattern.exec(str)+"|");  //|goog,goog| 第一个表示返回的所有分组，第二个goog表示返回的第一个分组匹配到的字符串
alert(str.match(pattern));  //goog,le,a  返回所有匹配到的字符串


var pattern=/^\s+(.+?)\s+$/;   //  /.+/表示贪婪模式   /.+?/表示惰性模式
var str="      goog le       ";
alert("|"+str.replace(pattern,"$1")+"|");  //将匹配的结果用第一个分组的匹配结果字符串替换
alert(RegExp.$1);  //可以查看第一个分组的匹配结果

*/