Javascript——正则表达式元字符

最新推荐文章于 2024-10-19 22:39:35 发布

慢慢学编程

最新推荐文章于 2024-10-19 22:39:35 发布

阅读量196

点赞数

分类专栏：慢慢找工作文章标签：正则表达式 javascript

本文链接：https://blog.youkuaiyun.com/weixin_40492102/article/details/104139638

版权

慢慢找工作专栏收录该内容

50 篇文章

订阅专栏

本文详细介绍了正则表达式中的各种元字符及其用法，包括如何匹配特定字符、数字、字母、特殊符号以及空白字符等。通过具体示例展示了元字符在字符串匹配中的应用。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>正则表达式——元字符</title>
</head>

<body>

</body>
<script>
    var reg = /[abc]/;
    var str = "a";
    document.write("<br>--------------元字符[] 匹配括号内的任意字符------------------<br>");
    document.write(" var reg = /[abc]/;<br>");
    document.write(" var str = a;<br>");
    document.write("reg.test(str) <br>");
    document.write("结果====>" + reg.test(str));

    var reg1 = /[^abc]/;
    var str = "a";
    document.write("<br>--------------元字符[^] 匹配不是括号内的任意字符------------------<br>");
    document.write(" var reg = /[^abc]/;<br>");
    document.write(" var str = a;<br>");
    document.write("reg.test(str); <br>");
    document.write("结果====>" + +reg1.test(str));


    var reg2 = /[2-9]/;
    var num = 1;
    document.write("<br>--------------元字符/[2-9]/ 匹配0-9任意数字------------------<br>");
    document.write(" var reg = /[2-9]/;<br>");
    document.write(" var num = 1;<br>");
    document.write("reg.test(num); <br>");
    document.write("结果====>" + reg2.test(num));

    var reg3 = /[a-z]/;
    var str = "a";
    document.write("<br>--------------元字符/[a-z]/匹配a-z任意字母------------------<br>");
    document.write("var reg = /[a-z]/;<br>");
    document.write("var str = a;<br>");
    document.write("reg.test(str); <br>");
    document.write("结果====>" + reg3.test(str));
    document.write("<br>var str2 = A;<br>");
    var str2 = "A";
    document.write("reg.test(str2); <br>");
    document.write("结果====>" + reg3.test(str2));


    var reg4 = /[0-9a-zA-Z]/;
    var num = "#";
    document.write("<br>--------------元字符/[0-9a-zA-Z]/ 匹配任意数字字符------------------<br>");
    document.write(" var reg = /[0-9a-zA-Z]/;<br>");
    document.write(" var num = #;<br>");
    document.write("reg4.test(num); <br>");
    document.write("结果====>" + reg4.test(num));

    var reg5 = /\d/;
    var str = "1";
    document.write("<br>--------------元字符/\d/ 匹配数字------------------<br>");
    document.write(" var reg = /\d/;<br>");
    document.write(" var str = 1;<br>");
    document.write("reg.test(str) <br>");
    document.write("结果====>" + reg5.test(str));

    var reg6 = /\D/;
    var str = "1";
    document.write("<br>--------------元字符/\D/ 匹配非数字------------------<br>");
    document.write(" var reg = /\D/;<br>");
    document.write(" var str = 1;<br>");
    document.write("reg.test(str) <br>");
    document.write("结果====>" + reg6.test(str));

    var reg7 = /\w/;
    var str = "#";
    document.write("<br>--------------元字符/\w/ 匹配数字字母下划线等同于[0-9a-zA-Z_]------------------<br>");
    document.write(" var reg = /\w/;<br>");
    document.write(" var str = #;<br>");
    document.write("reg.test(str) <br>");
    document.write("结果====>" + reg7.test(str));

    var reg8 = /\W/;
    var str = "#";
    document.write("<br>--------------元字符/\W/ 匹配非数字字母下划线------------------<br>");
    document.write(" var reg = /\W/;<br>");
    document.write(" var str = #;<br>");
    document.write("reg.test(str) <br>");
    document.write("结果====>" + reg8.test(str));

    var reg8 = /\s/;
    var str = " ";
    document.write("<br>--------------元字符/\s/ 匹配空格------------------<br>");
    document.write(" var reg = /\s/;<br>");
    document.write(" var str = ' ';<br>");
    document.write("reg.test(str) <br>");
    document.write("结果====>" + reg8.test(str));

    var reg9 = /\S/;
    var str = " ";
    document.write("<br>--------------元字符/\S/ 匹配非空格------------------<br>");
    document.write(" var reg = /\S/;<br>");
    document.write(" var str = ' ';<br>");
    document.write("reg.test(str) <br>");
    document.write("结果====>" + reg9.test(str));

    var reg10 = /\b\s/;
    var str10 = "a ";
    document.write("<br>--------------元字符/\bs/ 匹配边界------------------<br>");
    document.write(" var reg = /\b/;<br>");
    document.write(" var str = ' a';<br>");
    document.write("reg.test(str) <br>");
    document.write("结果====>" + reg10.test(str10));

    var reg11 = /./;
    var str11 = "你好";
    document.write("<br>--------------元字符/./ 除换行符之外的任意字符------------------<br>");
    document.write(" var reg = /./;<br>");
    document.write(" var str = '你好';<br>");
    document.write("reg.test(str) <br>");
    document.write("结果====>" + reg11.test(str11));

    var str12 = "\n";
    document.write(" <br>var str2 = '\n';<br>");
    document.write("reg.test(str2) <br>");
    document.write("结果====>" + reg11.test(str12));
</script>

</html>