正则入门

正则表达式必知必会（修订版）

//匹配一组字符串

//[ns]a..xls
var baseText4 = "na1.xls
1as.xls
ca1.xls
sa1.xls"

//[Rr]eg[Ee]x
var baseText5 = "The phrase 'regular expression' is often abbreviated ad RegEx or regex"

//[ns]a[0-9].xls
var baseText6 = "na1.xls
1as.xls
ca1.xls
sa1.xls
sam.xls"

//#[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]
var baseText7 = "background:#336633;color:#f1f1f1;padding:10px;"

//取非匹配
//[ns]a[^0-9].xls
// baseText6


//元字符 ： 无法用本身代表本身
// .   [  ]  等

// myArray[[O-9]]
var baseText8 = " var myArray = new Array()" +
    "for(myArray[0]==0){};  myArray[1]==1"

// \
var baseText9 = "\home\ben\sss"

//空白元字符
// []  f 
 
 	 v

// d 数字  D 非数字

// w 字母数字下划线  W 非字母数字下划线

var baseText10 = "11213
1d23d
22212
_ssd123
abcde
_2d21d"

// s 空白字符串 S 非空白字符串

//十六进制、 八进制
//十六进制  x
//八进制   

//POSIX字符 可移植操作系统接口


//
//重复匹配
//

// w{2,5}@baidu.com
var baseText11 = "b@baidu.com 
ben@baidu.com
4093@baidu.com"

//  w+@w+.w+
var baseText12 = 'send personal email to ben@forta.com 
For questions about a book use support@forta.com 
Feel free to send unsolicited email to spam@forta.com '


//[w.]+@[w.]+.w+
var baseText13 =  'send personal email to ben@forta.com or ben.forta@firta.com 
' +
    'For questions about a book use support@forta.com 
' +
    'if you message is ugrent try ben@urgent.forta.com.
'+
    'Feel free to send unsolicited email to spam@forta.com '

//w+[w.]*@[w.]+.w+
var baseText14 = "hello .ben@forta.com is my email address"

//http[s]?://[w./]*   or  https?://[w./]*
var baseText15 = "The URL is http://www.forta.com/ , 
" +
    "to connect securely use https://www.forta.com/ instead.
" +
    "https://www.baidu.com/se/"

//匹配的重复次数

//+ * 匹配的字符个数没有上限

// + * ？至少匹配0个或者1个字符

// {} 来设定一个精确地匹配次数的值


//  d{1,2}[-/]d{1,2}[-/]d{2,4}  匹配  日期 月份 年份
var baseText16 = "4/8/03
10-6-2004
+2/2/2
01-01-01"


// d+:$d{3,}.d{2}   寻找大于$100的
var baseText17 = '1001:$496.80 
1002:$1290.69
' +
    '1003:$26.43
1004:$613.42
1005:$5.23'

// 贪婪型匹配  *  + {n,} 他们会尽可能从一行文本的头部匹配到末尾

// 懒惰型匹配  *？ +? {n,}?   他们会匹配尽可能少的字符

// <[Bb]>.*?</[Bb]> 匹配b标签
var baseText18 = 'This offer is not available to customers living in <B>ak</B> and <B>HI</B>'


//
//位置匹配
//

// cat
var baseText19 = 'The cat scattered his food all over the room'
// B-B 多个单词边界
var baseText20 = 'the cat scattered his food all over   -    the room '

// <?xml.*?>
var baseText21 = '<?xml version="1.0" encoding="UTF-8" ?> 
' +
    '<wsdl:definition-src xmlns:wsdl="http://www.w3.org/1999/html">'

// ^s*<?xml.*?>   非空开头查找xml
var baseText22 = 'this is bad ,real bad 
' +
    '<?xml version="1.0" encoding="UTF-8" ?> 
' +
    '<wsdl:definition-src xmlns:wsdl="http://www.w3.org/1999/html">'

//

//分行匹配模式

//(?m)^s*//.*$ 查找注释的正则


//
//子表达式
//
//

//(d{1,3}.){3}d{1,3}  ip 查找
var baseText23 = 'Pinging hog.forta.com [12.159.46.200] 
' +
    'with 32 bytes of data:'

//(19|20)d{2} 查找4位年份
var baseText24 = "ID:042 
" +
    "sex: M
" +
    "DOB: 1967-08-17
" +
    "Status: Active"

//一个完整的ip匹配
//(((d{1,2})|(1d{2})|(2[0-4]d)|(25[0-5])).){3}((d{1,2})|(1d{2})|(2[0-4]d)|(25[0-5]))




//
//回溯引用： 前后一致匹配
//
//回溯允许后面的正则引用前面的匹配结果
//[ ]+(w+)[ ]+1
var baseText25 = 'this is a block of text, several words here are are repeated,
' +
    ' and and they should not be .'
//<[hH]([1-6])>.*?</[hH]1>  正确匹配每一个H标签 （不会匹配“<h2></h1>”）



//回溯例子：  mail替换
//replace( (w+[w.]*@[w.]+.w+) , <a href="mailto:$1">$1</a> )
// 替换前
var baseText26 = "my email is  40935539@qq.com, welcome send to me "
// 替换后
// my email is  <a href="mailto:409355439@qq.com">409355439@qq.com</a>, welcome send to me

//替换前
var baseText27 = "313 - 555 - 1234
" +
    "248 - 555 - 9999
" +
    "810 - 555 - 9000"
// replace( (d{3})( - )(d{3})( - )(d{4})  , ($1) $3 - $5 )
//替换后
// (313) 555 - 1234 (248) 555 - 9999 (810) 555 - 9000


//
//前后查找  JS不支持向后查找
//

//lookahead



//lookbehind
var baseText28 = "http://www.forta.com
" +
    "http://mail.forta.com
" +
    "ftp://ftp.forta.com"


//向前查找 + 向后查找
//(?<=([hH][1-9]>)).*(?=</[hH][1-9]>)

//example:      " <h3>REGEXP</h3>"

//取非
//正向前查找(?=)  负向前查找(?!)
//正向前查找(?<=)  负向后查找(?<!)

//(?<!$)d+ 查找不含$的数字
var baseText29 = "i paid $30 for 100 apples, 50 organges ,and 60 pears . i saved $5 on this order ."