问题,(？=(？:[^']*'[^']*')*[^']*$)

Question

C#Regex Split - 引号外的逗号

var result = Regex.Split(samplestring, ",(?=(?:[^\"]*\"[^\"]*')*[^\"]*$)");

我有问题要了解它是如何工作的.

具体来说,我不知道这里匹配的是什么？

",(?=(?:[^\"]*\"[^\"]*\")*[^\"]*$)")
                     ^

这是不是意味着

有0或更多 (?=(?:[^\"]*\"[^\"]*')

更新样本输入

2,1016,7/31/2008 14:22,Geoff Dalgas,6/5/2011 22:21,http://stackoverflow.com,"Corvallis, OR",7679,351,81,b437f461b3fd27387c5d8ab47a293d35,34

使用以下代码进行测试:

string samplestring = "2,1016,7/31/2008 14:22,Geoff Dalgas,6/5/2011 22:21,http://stackoverflow.com,\"Corvallis, OR\",7679,351,81,b437f461b3fd27387c5d8ab47a293d35,34";

Answer 1

这意味着该组(?:[^']*'[^']*')匹配零次或多次.

,       // match one comma
(?=     // Start a positive lookAHEAD assertion
(?:     // Start a non-capturing group
[^']*   // Match everything but a single-quote zero or more times
'       // Match one single-quote
[^']*   // Match everything but a single-quote zero or more times
'       // Match one single-quote
)*      // End group and match it zero or more times
[^']*   // Match everything but a single-quote zero or more times
$)      // end lookAHEAD