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javascript正则表达式——元字符

JavaScript正则表达式
2023-09-14 08:58:23 时间

元字符（Metacharacter）是拥有特殊含义的字符：

         元字符        描述                 

（1）   .              查找单个字符，除了换行和行结束符。

例子：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>点</title>
</head>
<body>
    <script type="text/javascript">
        str='index and php 2 and Php and pHp 3 and indox and 20 indax and indBx andpcp and pp and p p and p-p and p_p and p\np and p9p';
        arr = str.match(/p.p/ig)//查找单个字符，除了换行和行结束符。
        alert(arr);
    </script>
</body>
</html>

效果如图：

 

（2）\w          查找单词字符。(查找字母、数字、下划线，注意不包括“-”中间横线，如下例子)

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>反斜线小写w查找单词字符</title>
</head>
<body>
    <script type="text/javascript">
        str='index and php 2 and Php and pHp 3 and indox and 20 indax and indBx andpcp and pp and p p and p-p and p_p and p\np and p9p';
        arr = str.match(/p\wp/ig)//反斜线小写w查找单词字符
        alert(arr);
    </script>
</body>
</html>

效果图：

(3) \W      查找非单词字符。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>反斜线大写W查找非单词字符</title>
</head>
<body>
    <script type="text/javascript">
        str='index and php 2 and Php and pHp 3 and indox and 20 indax and indBx andpcp and pp and p p and p-p and p_p and p\np and p9p';
        arr = str.match(/p\Wp/ig)//反斜线大写W查找非单词字符
        alert(arr);
    </script>
</body>
</html>

效果图：

（4）\d    查找数字。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>反斜线小写d</title>
</head>
<body>
    <script type="text/javascript">
        str='index and php 2 and Php and pHp 3 and indox and 20 indax and indBx andpcp and pp and p p and p-p and p_p and p\np and p9p';
        arr = str.match(/p\dp/ig)//查找数字。
        alert(arr);
    </script>
</body>
</html>

(5)\D     查找非数字字符。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>反斜线大写D</title>
</head>
<body>
    <script type="text/javascript">
        str='index and php 2 and Php and pHp 3 and indox and 20 indax and indBx andpcp and pp and p p and p-p and p_p and p\np and p9p';
        arr = str.match(/p\Dp/ig)//查找非数字。
        alert(arr);
    </script>
</body>
</html>

 

(6)\s    查找空白字符。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>反斜线小写s,查找空白字符。</title>
</head>
<body>
    <script type="text/javascript">
        str='index and php 2 and Php and pHp 3 and indox and 20 indax and indBx andpcp and pp and p p and p-p and p_p and p\np and p9p';
        arr = str.match(/p\sp/ig)//反斜线小写s,查找空白字符。
        alert(arr);
    </script>
</body>
</html>

 （7）\S     查找非空白字符。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>反斜线大写S,查找非空白字符。</title>
</head>
<body>
    <script type="text/javascript">
        str='index and php 2 and Php and pHp 3 and indox and 20 indax and indBx andpcp and pp and p p and p-p and p_p and p\np and p9p';
        arr = str.match(/p\Sp/ig)//反斜线大写S,查找非空白字符。
        alert(arr);
    </script>
</body>
</html>

(8)\b     匹配单词边界。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>反斜线小写b,匹配单词边界。</title>
</head>
<body>
    <script type="text/javascript">
        str='index and php 2 and Php and pHp 3 and indox and 20 indax and indBx andpcp and pp and p p and p-p and p_p and p\np and p9p';
        arr = str.match(/\bp.p/ig)//反斜线小写b,匹配单词边界。
        alert(arr);
    </script>
</body>
</html>

(9)\B    匹配非单词边界。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>反斜线大写B,匹配非单词边界。</title>
</head>
<body>
    <script type="text/javascript">
        str='index and php 2 and Php and pHp 3 and indox and 20 indax and indBx andpcp and pp and p p and p-p and p_p and p\np and p9p';
        arr = str.match(/\Bp.p/ig)//反斜线大写B,匹配非单词边界。
        alert(arr);
    </script>
</body>
</html>

 

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