如何使用正則表達式來獲取字符串的特定部分

Question

我正在創建一個基於Sinatra的應用程序，並試圖使用正則表達式來解析長字符串以從中拉出鏈接。

這裏的有關信息字符串的一個片段，我需要提取：

time=18ms\n[INFO] Calculating CPD for 0 files\n[INFO] CPD calculation finished\n[INFO] Analysis report generated in 325ms, dir size=14 KB\n[INFO] Analysis reports compressed in 187ms, zip size=8 KB\n[INFO] Analysis report uploaded in 31ms\n[INFO] ANALYSIS SUCCESSFUL, you can browse http://sonar.company.com/dashboard/index/com.company.paas.maventestproject:MavenTestProject\n[INFO] Note that you will be able to access the updated dashboard once the server has processed the submitted analysis report\n[INFO] More about the report processing at http://sonar.company.com/api/ce/task?id=AVhFxTkyob-dgWZqnfIn\n[INFO] ----------------------------------------------------------------------- 

我需要能夠拉以下幾點：

http://sonar.company.com/api/ce/task?id=AVhFxTkyob-dgWZqnfIn 

我得到的最接近是與/(?=http).[a*-z]*/但這不是接近我所需要的，因爲它發現615匹配，而不是1.

問題還在於，身份證AVhFxTkyob-dgWZqnfIn不是stat ic，每個版本更改。

我一直在使用Rubular.com找到我需要使用的正確的正則表達式。

Answer 1

>> string = '[your long string here]' 
>> regex = /(http:[\w\/.?=-]+)(\\n)/ 
>> string.scan(regex).first.first 
=> "http://sonar.company.com/api/ce/task?id=AVhFxTkyob-dgWZqnfIn" 

按照上面的例子中，我結束了修改正則表達式如下：

(http:\/\/sonar[\w\/.?=-]+task[\w\/.?=-]+(?!.\\n)) 

..而這樣的回報吧：

string.scan(regex).first.first 

我之所以修改正則表達式是因爲前一個正則表達式在插入完整字符串而不是OP中的摘錄時以很多結果結束。

Answer 2

有很好的測試工具，可以讓你的工作更輕鬆。我推薦使用URI的extract方法：

require 'uri' 

str = "time=18ms\n[INFO] Calculating CPD for 0 files\n[INFO] CPD calculation finished\n[INFO] Analysis report generated in 325ms, dir size=14 KB\n[INFO] Analysis reports compressed in 187ms, zip size=8 KB\n[INFO] Analysis report uploaded in 31ms\n[INFO] ANALYSIS SUCCESSFUL, you can browse http://sonar.company.com/dashboard/index/com.company.paas.maventestproject:MavenTestProject\n[INFO] Note that you will be able to access the updated dashboard once the server has processed the submitted analysis report\n[INFO] More about the report processing at http://sonar.company.com/api/ce/task?id=AVhFxTkyob-dgWZqnfIn\n[INFO] -----------------------------------------------------------------------" 

URI.extract(str) 
# => ["http://sonar.company.com/dashboard/index/com.company.paas.maventestproject:MavenTestProject", 
#  "http://sonar.company.com/api/ce/task?id=AVhFxTkyob-dgWZqnfIn"] 

然後，它找到你想要的鏈接，並使用它的一個簡單的事情。

您還需要注意URI爲該方帶來的所有其他方法，因爲它瞭解如何根據RFC分解和構建URI。

不要推出自己的代碼或正則表達式來完成別人已經完成的工作，特別是當代碼經過良好測試時。你會避免別人會陷入的陷阱。 URI的作者/維護者管理內置模式，所以我們不需要。而且，它比你想象的要複雜得多，比如：

URI::REGEXP::PATTERN::ABS_URI 
"[a-zA-Z][\\-+.a-zA-Z\\d]*:(?:(?://(?:(?:(?:[\\-_.!~*'()a-zA-Z\\d;:&=+$,]|%[a-fA-F\\d]{2})*@)?(?:(?:[a-zA-Z0-9\\-.]|%\\h\\h)+|\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}|\\[(?:(?:[a-fA-F\\d]{1,4}:)*(?:[a-fA-F\\d]{1,4}|\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3})|(?:(?:[a-fA-F\\d]{1,4}:)*[a-fA-F\\d]{1,4})?::(?:(?:[a-fA-F\\d]{1,4}:)*(?:[a-fA-F\\d]{1,4}|\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}))?)\\])(?::\\d*)?|(?:[\\-_.!~*'()a-zA-Z\\d$,;:@&=+]|%[a-fA-F\\d]{2})+)(?:/(?:[\\-_.!~*'()a-zA-Z\\d:@&=+$,]|%[a-fA-F\\d]{2})*(?:;(?:[\\-_.!~*'()a-zA-Z\\d:@&=+$,]|%[a-fA-F\\d]{2})*)*(?:/(?:[\\-_.!~*'()a-zA-Z\\d:@&=+$,]|%[a-fA-F\\d]{2})*(?:;(?:[\\-_.!~*'()a-zA-Z\\d:@&=+$,]|%[a-fA-F\\d]{2})*)*)*)?|/(?:[\\-_.!~*'()a-zA-Z\\d:@&=+$,]|%[a-fA-F\\d]{2})*(?:;(?:[\\-_.!~*'()a-zA-Z\\d:@&=+$,]|%[a-fA-F\\d]{2})*)*(?:/(?:[\\-_.!~*'()a-zA-Z\\d:@&=+$,]|%[a-fA-F\\d]{2})*(?:;(?:[\\-_.!~*'()a-zA-Z\\d:@&=+$,]|%[a-fA-F\\d]{2})*)*)*)(?:\\?(?:(?:[\\-_.!~*'()a-zA-Z\\d;/?:@&=+$,\\[\\]]|%[a-fA-F\\d]{2})*))?|(?:[\\-_.!~*'()a-zA-Z\\d;?:@&=+$,]|%[a-fA-F\\d]{2})(?:[\\-_.!~*'()a-zA-Z\\d;/?:@&=+$,\\[\\]]|%[a-fA-F\\d]{2})*)"