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PHP一些常用的正则表达式_PHP

Jun 01, 2016 pm 12:34 PM
giptextmatchCommonly usedexpression

正则表达式

匹配中文字符的正则表达式: [\u4e00-\u9fa5]

  匹配双字节字符(包括汉字在内): [^\x00-\xff]

  应用:计算字符串的长度(一个双字节字符长度计2,ASCII字符计1)

String.prototype.len=function(){return this.replace([^\x00-\xff]/g,"aa").length;}

  匹配空行的正则表达式: \n[\s| ]*\r

  匹配HTML标记的正则表达式: /.*|/

  匹配首尾空格的正则表达式: (^\s*)|(\s*$)

  应用:javascript中没有像vbscript那样的trim函数,我们就可以利用这个表达式来实现,如下:

String.prototype.trim = function() {
return this.replace(/(^\s*)|(\s*$)/g, "");
}

  利用正则表达式分解和转换IP地址:

  下面是利用正则表达式匹配IP地址,并将IP地址转换成对应数值的javascript程序:

function IP2V(ip) {
re=/(\d )\.(\d )\.(\d )\.(\d )/g //匹配IP地址的正则表达式
if(re.test(ip)) {
return RegExp.*Math.pow(255,3)) RegExp.*Math.pow(255,2)) RegExp.*255 RegExp.*1
}
else {
throw new Error("Not a valid IP address!")
}
}

  不过上面的程序如果不用正则表达式,而直接用split函数来分解可能更简单,程序如下:

var ip="10.100.20.168"
ip=ip.split(".")
alert("IP值是:" (ip[0]*255*255*255 ip[1]*255*255 ip[2]*255 ip[3]*1))

  匹配Email地址的正则表达式: \w ([- .]\w )*@\w ([-.]\w )*\.\w ([-.]\w )*

  匹配网址URL的正则表达式: http://([\w-] \.) [\w-] (/[\w- ./?%&=]*)?

  利用正则表达式去除字串中重复的字符的算法程序:

var s="abacabefgeeii"
var s1=s.replace(/(.).*/g,"")
var re=new RegExp("[" s1 "]","g")
var s2=s.replace(re,"")
alert(s1 s2) //结果为:abcefgi

  用正则表达式从URL地址中提取文件名的javascript程序,如下结果为page1

s="http://www.9499.net/page1.htm"
s=s.replace(/(.*\/)([^\.] ).*/ig,"")
alert(s)

  利用正则表达式限制网页表单里的文本框输入内容:

  用正则表达式限制只能输入中文:

onkeyup="value=value.replace(/[^\u4E00-\u9FA5]/g,'')" onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\u4E00-\u9FA5]/g,''))"

  用正则表达式限制只能输入全角字符:

onkeyup="value=value.replace(/[^\uFF00-\uFFFF]/g,'')" onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\uFF00-\uFFFF]/g,''))"

  用正则表达式限制只能输入数字:

onkeyup="value=value.replace(/[^\d]/g,'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))"

  用正则表达式限制只能输入数字和英文:

onkeyup="value=value.replace(/[\W]/g,'') "onbeforepaste="clipboardData.setData('text',clipboardData.getData('text').replace(/[^\d]/g,''))"
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