正则表达式是一种具有特定模式的用来匹配文本的字符串

preg_match 匹配

$pattern = '/php/';
$subject = "php 是最好的编程语言,php 没有之一!";

$result = preg_match($pattern,$subject);

if($result){
    echo "<h1>匹配成功</h1>";
}else{
    echo "<h1>匹配不成功</h1>";
}

preg_match_all 匹配所有

$pattern = '/php/';
$subject = "php是最好的编程语言,不会php的程序员不是好程序员!";
$result = preg_match_all($pattern,$subject,$matches);
var_dump($result);
var_dump($matches);

//preg_match===
//int 1
//array (size=1)
//  0 => string 'php' (length=3)

//preg_match_all ====
//int 2
//array (size=1)
//  0 =>
//    array (size=2)
//      0 => string 'php' (length=3)
//      1 => string 'php' (length=3)

preg_replace 正则替换

preg_filter() 等价于 preg_replace() ,但它仅仅返回与目标匹配的结果

$pattern = '/www\..*\.com/';
$replacement = 'www.test.com';
$subject = [
    'www.baidu.com',
    'www.google.com',
    'coding.test.com'
];
$result = preg_replace($pattern,$replacement,$subject);
var_dump($result);
//array(3) {
//    [0] =>
//  string(12) "www.test.com"
//    [1] =>
//  string(12) "www.test.com"
//    [2] =>
//  string(15) "coding.test.com"
//}

$result1 = preg_filter($pattern,$replacement,$subject);
var_dump($result1);
//array(2) {
//    [0] =>
//  string(12) "www.test.com"
//    [1] =>
//  string(12) "www.test.com"
//}

正则搜索并使用回调替换

$pattern = '/(.*)(\d{4})(-\d{2}-\d{2})/';
$subject = "今天是2020-01-14";
$result = preg_replace_callback($pattern,'nextyear',$subject);
var_dump($result);

function nextyear($vars){
    return '明年的'.$vars[1].($vars[2]+1).$vars[3];//string(28) "明年的今天是2021-01-14"
}

//array (size=4)
//  0 => string '今天是2020-01-14' (length=19)
//  1 => string '今天是' (length=9)
//  2 => string '2020' (length=4)
//  3 => string '-01-14' (length=6)

preg_grep_invert 返回没有被匹配替换到的

$pattern = '/www\..*\.com/';
$subject = [
    'www.baidu.com',
    'www.google.com',
    'coding.imooc.com'
];
$result = preg_grep($pattern,$subject,preg_grep_invert);
var_dump($result);//string(16) "coding.imooc.com"

preg_split 按照指定规则分割字符串转数组

$pattern = '/\||,|\s/';
$replacement = '|';
$subject = "php|asp,jsp html";

$result1 = preg_split($pattern,$subject,3);
var_dump($result1);

//array (size=4)
//  0 => string 'php' (length=3)
//  1 => string 'asp' (length=3)
//  2 => string 'jsp' (length=3)
//  3 => string 'html' (length=4)

转义正则表达式字符

$str = '<a href="http://www.test.com">测试网</a>';
$result = preg_quote($str,'/');
$pattern = '/'.$result.'/';
$subject = '<a href="http://www.test.com">测试网</a>';
echo preg_match($pattern,$subject);

//\<a href\="http://www\.test\.com"\>测试网\</a\>

()单独获取

$pattern = '/[\da-z]+([\._\-]*[\da-z]+)*@[\da-z]+([\.\-][\da-z]+)*\.[a-z]+/i';
$subject = <<<php
    //imooc123@qq.com
    //imooc.123@qq.com
    //imooc_123@qq123.com
    //imooc--123@qq.com
    //imooc123@qq.com.cn
    //imooc123@vip-qq.com
php;

preg_match_all($pattern,$subject,$matches);
var_dump($matches);
//array(3) {
//    [0] =>//打印出所有匹配到的
//  array(6) {
//        [0] =>
//    string(15) "imooc123@qq.com"
//        [1] =>
//    string(16) "imooc.123@qq.com"
//        [2] =>
//    string(19) "imooc_123@qq123.com"
//        [3] =>
//    string(17) "imooc--123@qq.com"
//        [4] =>
//    string(18) "imooc123@qq.com.cn"
//        [5] =>
//    string(19) "imooc123@vip-qq.com"
//  }
//  [1] =>//打印出第一个()里的
//  array(6) {
//        [0] =>
//    string(0) ""
//        [1] =>
//    string(4) ".123"
//        [2] =>
//    string(4) "_123"
//        [3] =>
//    string(5) "--123"
//        [4] =>
//    string(0) ""
//        [5] =>
//    string(0) ""
//  }
//  [2] =>//打印出第二个()里的
//  array(6) {
//        [0] =>
//    string(0) ""
//        [1] =>
//    string(0) ""
//        [2] =>
//    string(0) ""
//        [3] =>
//    string(0) ""
//        [4] =>
//    string(4) ".com"
//        [5] =>
//    string(3) "-qq"
//  }
//}

ajax注册表单案例

index.html

<!doctype html>
<html lang="en">
<head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8" />
    <link rel="stylesheet" type="text/css" href="css/base.css" />
    <link rel="stylesheet" type="text/css" href="css/register.css" />
    <title>用户注册表单验证</title>
    <script src="js/jquery.js"></script>
</head>

<body>
<div class="wrapper container">
    <h2>用户注册</h2>
    <form onsubmit="return post(this)">
        <p class="clearfix">
            <label class="one">手机号码:</label>
            <input name="telphone" class="text" placeholder="请输入手机号" />
            <label class="error">请输入正确的手机号</label>
        </p>
        <p class="clearfix">
            <label class="one" >校验码:</label>
            <input name="code" class="code" type="text"  placeholder="请输入手机6位校验码" />
            <input class="get_code" type="button" value="获取验证码" />
            <label class="error">请填写手机接收到的6位数校验码</label>
        </p>
        <p class="clearfix">
             <label class="one">登录密码:</label>
            <input name="password" type="password"  class="text" placeholder="请输入6-16位密码" />
            <label class="error">密码在6-16个字符之间</label>
        </p>
        <p class="clearfix">
            <label class="one">确认密码:</label>
            <input name="c_password" type="password"  class="text" placeholder="请再次输入密码" />
            <label class="error">确认密码和密码不一致</label>
        </p>
        <p class="clearfix">
            <label class="one">姓名:</label>
            <input name="name" type="text" class="text" placeholder="请输入2-6位中文" />
            <label class="error">请输入2-6位中文</label>
        </p>
        <p class="clearfix">
            <label class="one">身份证:</label>
            <input name="idcard" type="text"  class="text"  placeholder="请输入18位二代身份证号码" />
            <label class="error">请输入18位二代身份证号码</label>
        </p>
        <p class="clearfix">
            <label class="one">邮箱:</label>
            <input name="email" type="text" class="text" placeholder="请输入email邮箱" />
            <label class="error">email邮箱不正确</label>
        </p>
           <p class="clearfix"><input class="submit" type="submit" value="立即注册"/></p>
    </form>
</div>
<script>
    function post(obj) {
        var postdata = $(obj).serialize();
        $.post('php/check.php',{postdata:postdata},function (data) {
            if(data.code){
                $("input[name="+data.sign+"]").siblings('.error').show();
            }else{
                location.href = 'ok.html';
            }
        },'json');
        return false;
    }
</script>
</body>
</html>

ok.html

<!doctype html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>title</title>
</head>
<body>
    <h1>注册成功!</h1>
</body>
</html>

base.css

/* css document */
*{margin:0; padding:0;}
a{text-decoration:none; cursor:pointer;}
li{list-style:none;}
img{border:none;}
html,body{ font-size:16px; font-family:"微软雅黑"; overflow-x:hidden;}

.wrapper{width:820px; margin:0 auto;}
.left{float:left;}
.right{float:right;}
.clearfix:after{content:"."; display:block; clear:both; font-size:0; overflow:hidden; height:0;}
.clearfix{zoom:1;}
.red{color:#f93;}

.mt{ margin-top:10px;}
.mr{ margin-right:10px;}
.mb{ margin-bottom:10px;}
.ml{ margin-left:10px;}


/*----header-----*/

.header{height:35px; line-height:35px; background:#5a84d1; color:#fff; font-size:14px;}
.header a{color:#fff;}

.weixin{position:relative; display:block; width:120px; height:38px; text-align:center;}
.wx{display:inline-block; width:35px; height:35px; background:url(../img/weixinhui.png) no-repeat;}
.wx:hover{background:url(../img/weixin.png) no-repeat;}
.erweima{position:absolute; top:35px; left:0; display:block; width:120px; height:120px; border:1px solid #999; z-index:100;}

.header .right #time{margin-left:20px;}

.top{height:74px; width:1140px; margin:10px auto}
/*-------logo-------*/
.logo{height:74px; margin-right:15px;}
.logo a{display:block;}
.slogo{width:170px; height:60px; margin-top:10px; padding-left:10px; overflow:hidden; border-left:1px solid #ccc; font-size:20px;}


/*-------nav-------*/
.nav{float:right; height:30px; margin-top:30px; line-height:30px;}
.nav li{float:left; position:relative; width:115px; text-align:center;}
.nav li a{font-size:20px; color:#3a3a3a;}
.nav li:hover > a{color:#28a7e1}
.nav li:hover > ul{visibility:visible; opacity:1; }
.nav li a {text-decoration:none; display:inline-block;
    -webkit-transition:color 0.2s linear, background 0.2s linear;
    -moz-transition:color 0.2s linear, background 0.2s linear;
    -o-transition:color 0.2s linear, background 0.2s linear;
    transition:color 0.2s linear, background 0.2s linear; }
.subnav {visibility:hidden; opacity:0; position:absolute; top:30px; left:0; z-index:100; width:115px; text-align:center; background:rgba(0,0,0,0.4); 
    -webkit-transition:opacity 0.2s linear, visibility 0.2s linear; 
    -moz-transition:opacity 0.2s linear, visibility 0.2s linear; 
    -o-transition:opacity 0.2s linear, visibility 0.2s linear; 
    transition:opacity 0.2s linear, visibility 0.2s linear; }
.subnav li{clear:both; width:100%; border:0 none;}
.subnav li a{display:inline-block; color:#fff;}
.subnav li:hover > a{color:#80eef5;}


/*-------footer-----*/
.footer{background:#eee;  padding-bottom:50px;}
.footer a{color:#000;}
.list1{margin:20px 15px 40px;}
.list1 li{height:40px; line-height:40px;}
.list1 a.first:hover{background:url(img/redicon.png) 0 6px no-repeat;}

.list1 a.first{/*float:left;*/margin-right:23px; text-indent:15px; font-weight:bold; color:#111;}

.sublist li{float:left;/**/ margin-right:11px;}
.sublist li a{color:#111;}

.par{text-align:center;}
.par a{padding:0 10px;}

.footer div.right{margin:20px 25px 40px 0; }


/*kefu*/
#sidekf{background:url(../img/222.png) no-repeat left bottom;width:225px; height:200px; position:fixed; _position:absolute; right:-139px;top:40px;_top:expression(documentelement.scrolltop+40);z-index:9;}
#sidekf .lnk{ float:left;width:225px;}
#sidekf .ovh{ float:right;width:35px; height:100px;}
#sidekf a{display:block;width:128px; margin-left:97px;}
.sidekf_qq1{height:33px; margin-top:35px;}
.sidekf_qq2{height:36px; margin-top:3px;}
.sidekf_qq3{height:36px; margin-top:3px;}

register.css

/* css document */

.container{margin:5px auto; border:1px solid #d8d8d8; background: #f9f9f9; padding:50px; font-family:"微软雅黑"}
.container h2{text-align:center; color:#333;}
form{margin:20px 0 0 120px;}
form p{margin-bottom:10px;}
form a{ color:#ff7702;}

h2{ line-height:60px; font-size:30px; color:#333;}
label{display:block; float:left; height:48px; line-height:48px; color:#f00; text-indent:10px;}
label.one{width:90px; height:48px; text-align:right; color:#333;}

input{float:left;font-size:16px; font-family:"微软雅黑"; color:#666;}
.text,.submit{border:1px solid #ccc; width:300px; height:46px; text-indent:10px;}
.error{display: none;}

.code{height:46px; width:180px; _line-height:46px; text-indent:10px;}
.get_code{height:48px; width:110px; margin-left:10px; border:1px solid #ccc; cursor:pointer;}

.agreement{margin-left:90px; height:30px; line-height:30px;font-size:12px;}
.agreement input{display:block; line-height:30px; height:12px; margin:8px 8px 0 5px; border:none; width:12px; background:url(../img/checkbox.png) no-repeat; }
.get_code{background:#337ab7; color:#fff;}

.submit{margin-left:90px; background:#f93; font-size:20px; letter-spacing:4px; color:#fff; cursor:pointer;}

p.last{margin-left:310px; font-size:16px;}
p.last input{ cursor:pointer;}

check.php

<?php
parse_str($_post['postdata'],$post);
if(!preg_match('/^1\d{10}$/',$post['telphone'])){
   echo json_encode(['code'=>1,'sign'=>'telphone']);
    return ;
}
if($post['code']!='123456'){
    echo json_encode(['code'=>1,'sign'=>'code']);
    return ;
}
if(!preg_match('/^.{6,16}$/',$post['password'])){
    echo json_encode(['code'=>1,'sign'=>'password']);
    return ;
}
if($post['c_password']!=$post['password']){
    echo json_encode(['code'=>1,'sign'=>'c_password']);
    return ;
}
if(!preg_match('/^[\x80-\xff]{6,18}$/',$post['name'])){
    echo json_encode(['code'=>1,'sign'=>'name']);
    return ;
}
if(!preg_match('/^\d{18}$/',$post['idcard'])){
    echo json_encode(['code'=>1,'sign'=>'idcard']);
    return ;
}
if(!preg_match('/^[\da-z]+([\._\-]*[\da-z]+)*@[\da-z]+([\.\-][\da-z]+)*\.[a-z]+$/',$post['email'])){
    echo json_encode(['code'=>1,'sign'=>'email']);
    return ;
}

//将合法数据写入数据库
echo json_encode(['code'=>0]);

//utf8编码下汉字unicode编码范围:\x80-\xff

//array (size=1)
//'postdata' => string 'telphone=111111&password=&c_password=&name=&idcard=&email=' (length=58)

//array (size=6)
//  'telphone' => string '111111' (length=6)
//  'password' => string '' (length=0)
//  'c_password' => string '' (length=0)
//  'name' => string '' (length=0)
//  'idcard' => string '' (length=0)
//  'email' => string '' (length=0)

基础知识补充:

在线调试工具
http://www.regexr.com/

“汉字”建议使用unicode编码再进行匹配
在线转码工具:http://tool.chinaz.com/tools/unicode.aspx

不可见原子

自定义原子

通用字符类型作原子

元字符
元字符就是指那些在正则表达式中具有特殊意义的专用字符

 

 边界限制符

量词

 

 禁止贪婪

? 

当该字符紧跟在任何一个其他限制符 (*, +, {n,}, {n,m})
后面时,匹配模式是非贪婪的。

u

模式修正符

模式单元
模式单元()的三个作用:
分组、限制多选结构、捕获文本

反向引用
反向引用:对模式单元中捕获的文本内容的引用
捕获的文本存储在临时缓冲区中,缓冲区编号范围为1-99,反向引用格式为:
\+编号
非捕获元字符 “ ?: ”

定界符
当使用正则函数的时候,模式需要由定界符闭合包裹。
分隔符可以使任意非字母数字、非反斜线、非空白字符。
经常使用的分隔符是正斜线(/)、hash符号(#) 以及取反符号(~)。
如果分隔符需要在模式内进行匹配,它必须使用反斜线进行转义

模式修正符