“正则表达式 练习：验证是否整数或小数”的版本间的差异

来自姬鸿昌的知识库
跳到导航 跳到搜索
（建立内容为“https://www.bilibili.com/video/BV1Eq4y1E79W?p=25”的新页面）
 
 
（未显示同一用户的2个中间版本）
第1行： 第1行：
 
https://www.bilibili.com/video/BV1Eq4y1E79W?p=25
 
https://www.bilibili.com/video/BV1Eq4y1E79W?p=25
 +
 +
要考虑正数和负数，比如：123、-345、34.89、-87.9、-0.01、0.45等
 +
 +
=== 我的实现 ===
 +
<syntaxhighlight lang="java">
 +
public class Homework02 {
 +
 +
    public static void main(String[] args) {
 +
 +
        String regex = "^-?\\d+\\.?\\d*$";
 +
 +
        String[] contents = {"123", "-345", "34.89", "-87.9", "-0.01", "0.45", "--123", "-0.123", "abc"};
 +
 +
        for (String content:contents) {
 +
            System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
 +
        }
 +
 +
    }
 +
 +
}
 +
</syntaxhighlight><syntaxhighlight lang="console">
 +
"123".matches(regex):true
 +
"-345".matches(regex):true
 +
"34.89".matches(regex):true
 +
"-87.9".matches(regex):true
 +
"-0.01".matches(regex):true
 +
"0.45".matches(regex):true
 +
"--123".matches(regex):false
 +
"-0.123".matches(regex):true
 +
"abc".matches(regex):false
 +
</syntaxhighlight>
 +
 +
 +
=== 视频里的实现 ===
 +
<syntaxhighlight lang="java">
 +
public class Homework02 {
 +
 +
    public static void main(String[] args) {
 +
 +
        String regex = "^[-+]?(0|[1-9]\\d*)(\\.\\d+)?$";
 +
 +
        String[] contents = {"123", "-345", "34.89", "-87.9", "-0.01", "0.45", "--123", "-0.123", "abc", "0.89", "01.89"};
 +
 +
        for (String content:contents) {
 +
            System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
 +
        }
 +
 +
    }
 +
 +
}
 +
</syntaxhighlight><syntaxhighlight lang="console">
 +
"123".matches(regex):true
 +
"-345".matches(regex):true
 +
"34.89".matches(regex):true
 +
"-87.9".matches(regex):true
 +
"-0.01".matches(regex):true
 +
"0.45".matches(regex):true
 +
"--123".matches(regex):false
 +
"-0.123".matches(regex):true
 +
"abc".matches(regex):false
 +
"0.89".matches(regex):true
 +
"01.89".matches(regex):false
 +
</syntaxhighlight>

2022年11月22日 (二) 07:32的最新版本

https://www.bilibili.com/video/BV1Eq4y1E79W?p=25

要考虑正数和负数，比如：123、-345、34.89、-87.9、-0.01、0.45等

我的实现

public class Homework02 {

    public static void main(String[] args) {

        String regex = "^-?\\d+\\.?\\d*$";

        String[] contents = {"123", "-345", "34.89", "-87.9", "-0.01", "0.45", "--123", "-0.123", "abc"};

        for (String content:contents) {
            System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
        }

    }

}

"123".matches(regex):true 
"-345".matches(regex):true 
"34.89".matches(regex):true 
"-87.9".matches(regex):true 
"-0.01".matches(regex):true 
"0.45".matches(regex):true 
"--123".matches(regex):false 
"-0.123".matches(regex):true 
"abc".matches(regex):false


视频里的实现

public class Homework02 {

    public static void main(String[] args) {

        String regex = "^[-+]?(0|[1-9]\\d*)(\\.\\d+)?$";

        String[] contents = {"123", "-345", "34.89", "-87.9", "-0.01", "0.45", "--123", "-0.123", "abc", "0.89", "01.89"};

        for (String content:contents) {
            System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
        }

    }

}

"123".matches(regex):true 
"-345".matches(regex):true 
"34.89".matches(regex):true 
"-87.9".matches(regex):true 
"-0.01".matches(regex):true 
"0.45".matches(regex):true 
"--123".matches(regex):false 
"-0.123".matches(regex):true 
"abc".matches(regex):false 
"0.89".matches(regex):true 
"01.89".matches(regex):false
取自“https://www.jihongchang.top/index.php?title=正则表达式_练习：验证是否整数或小数&oldid=3816”