[英]Java regular expression finding number
I'm trying to parse log using regex. 我正在尝试使用正则表达式解析日志。 Unfortunately I' stacked on following string.
不幸的是我堆在下面的字符串上。 Trying to find line beginning with time
试图找到时间开始的线
for example: 例如:
String p="11:33:00.0 2000 0.0 ....... # 0.0 ....... # 0.0 ....... # 0.0 ...";
I have following code: 我有以下代码:
public class Test {
public static void main(String[] args) {
String p="11:33:00.0 2000 0.0 ....... # 0.0 ....... # 0.0 ....... # 0.0 ...";
Pattern pat = Pattern.compile("^\\d\\d\\:\\d\\d*");
Matcher m = pat.matcher(p);
if (m.find()) {
System.out.println(m.start());
System.out.println(p.substring(m.start()));
}
}
}
this code prints nothing even if I tried just '^\\d\\d'. 即使我只是尝试'^ \\ d \\ d',此代码也不会打印任何内容。
if I'm correct '^' stands for line beginning '\\d' for any digit 如果我是正确的,则'^'代表以'\\ d'开头的任意数字行
I also tried to replace '^' with '\\A' If i change pattern to 我还尝试将'^'替换为'\\ A'如果我将模式更改为
pat = Pattern.compile("\\d\\d");
it returns position at 6. Can somebody tell me why the first code is not working?:) 它返回位置6。有人可以告诉我为什么第一个代码不起作用吗?
THX 谢谢
You need to print the group index 0 inside the if block, so that it would print the matched characters. 您需要在if块中打印组索引0,以便它将打印匹配的字符。
String p="11:33:00.0 2000 0.0 ....... # 0.0 ....... # 0.0 ....... # 0.0 ...";
Pattern pat = Pattern.compile("^\\d\\d\\:\\d\\d*");
Matcher m = pat.matcher(p);
if (m.find()) {
System.out.println(m.group(0));
}
Output: 输出:
11:33
On my computer your example Test.main worked fine, maybe it's dependant on JVM implementation. 在我的计算机上,您的示例Test.main运行良好,可能取决于JVM的实现。 I think if you open then you also need to close regex with question mark:
我认为,如果您打开,那么还需要用问号关闭正则表达式:
"^\\d\\d?"
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.