英文:
Regular expression: Replace everything before first occurence
问题
我有以下正则表达式，用于移除我的URL中的dev.部分。
String domain = "dev.mydomain.com";
System.out.println(domain.replaceAll(".*\\.(?=.*\\.)", ""));
输出：mydomain.com 但是当域名为dev.mydomain.com.pe或者dev.mydomain.com.uk时，我得到的结果只有.com.pe和.com.uk部分。
是否有一个修饰符可以在我的正则表达式上使用，以确保它只获取第一个.之前的部分（包括点）？
期望输出：
dev.mydomain.com -> mydomain.com
stage.mydomain.com.pe -> mydomain.com.pe
test.mydomain.com.uk -> mydomain.com.uk
英文:
I have the following regular expression that I'm using to remove the dev. part of my URL.
String domain = "dev.mydomain.com";
System.out.println(domain.replaceAll(".*\\.(?=.*\\.)", ""));
Outputs: mydomain.com but this is giving me issues when the domains are in the vein of dev.mydomain.com.pe or dev.mydomain.com.uk in those cases I am getting only the .com.pe and .com.uk parts.
Is there a modifier I can use on my regex to make sure it only takes what is before the first . (dot included)?
Desired output:
dev.mydomain.com -> mydomain.com
stage.mydomain.com.pe -> mydomain.com.pe
test.mydomain.com.uk -> mydomain.com.uk
答案1
得分: 1
你可以使用以下正则表达式：
^[^.]+\.(?=.*\.)
细节
^- 字符串开头[^.]+- 1个或多个非点字符\.- 一个点(?=.*\.)- 跟随任意0个或多个非换行字符，尽可能多，然后是一个点。
Java使用示例：
String result = domain.replaceFirst("^[^.]+\\.(?=.*\\.)", "");
英文:
You may use
^[^.]+\.(?=.*\.)
See the regex demo and the regex graph:
Details
^- start of string[^.]+- 1 or more chars other than dots\.- a dot(?=.*\.)- followed with any 0 or more chars other than line break chars as many as possible and then a..
Java usage example:
String result = domain.replaceFirst("^[^.]+\\.(?=.*\\.)", "");
答案2
得分: 0
以下正则表达式适用于您的情况。它将查找第一部分（如果存在），捕获字符串的剩余部分作为第二个匹配组，并用第二个匹配组替换字符串。.*?是非贪婪搜索，它将匹配直到遇到第一个点字符为止。
(.*?\.)?(.*\..*)
示例代码：
String domain = "dev.mydomain.com";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
domain = "stage.mydomain.com.pe";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
domain = "test.mydomain.com.uk";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
domain = "mydomain.com";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
输出：
mydomain.com
mydomain.com.pe
mydomain.com.uk
mydomain.com
英文:
Following regex will work for you. It will find first part (if exists), captures rest of the string as 2nd matching group and replaces the string with 2nd matching group. .*? is non-greedy search that will match until it sees first dot character.
(.*?\.)?(.*\..*)
sample code:
String domain = "dev.mydomain.com";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
domain = "stage.mydomain.com.pe";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
domain = "test.mydomain.com.uk";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
domain = "mydomain.com";
System.out.println(domain.replaceAll("(.*?\\.)?(.*\\..*)", "$2"));
output:
mydomain.com
mydomain.com.pe
mydomain.com.uk
mydomain.com
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