正則表達式提取字符串中每四個逗號的匹配項

Question

我正在嘗試創建一個正則表達式，以獲取以下字符串的輸出，並以4個逗號分隔的值的形式出現。 我嘗試了一些方法，但是它僅選擇每個逗號分隔的值。 我不知道如何獲得所需的輸出。

我嘗試過的正則表達式：

".*?"(?=,|$)

數據：

"T","Success","2","2","T","Success","6458960","1","F,"You do not have sufficient credit.","6458962","1"

要求：

"T","Success","2","2"  
"T","Success","6458960","1"  
"F,"You do not have sufficient credit.","6458962","1"

更新： “ F也用雙引號引起來，這是一個錯字，抱歉！”

“ T”，“成功”，“ 2”，“ 2”，“ T”，“成功”，“ 6458960”，“ 1”，“ F”，“您沒有足夠的信用。”，“ 6458962”， “ 1”

Answer 1

您只需要String.Split ：

string[] fields = str.Split(',');
for (int i = 0; i < fields.Length; i += 4)
    Console.WriteLine(string.Join(",", fields.Skip(i).Take(4)));

輸出：

"T","Success","2","2"
"T","Success","6458960","1"
"F,"You do not have sufficient credit.","6458962","1"

假定這不是真的csv數據。 否則，我建議使用支持引號的真實CSV解析器 。 但是似乎它們還是被破壞了（ ,"1","F,. ，所以F沒有用引號引起來）。

Answer 2

您可以使用以下正則表達式，但前提是F也必須用引號引起來：

((?:".+",){3}(?:".+"))

結果是：

匹配1 1. [0-21] "T","Success","2","2"

匹配2 1. [22-49] "T","Success","6458960","1"

匹配3 1. [50-104] "F","You do not have sufficient credit.","6458962","1"

正則表達式演示

如果數據的格式確實不一致，則必須手動解析或使用or條件修改正則表達式。

Answer 3

((?:"[^"]*"|[^,"])*(?:,(?:"[^"]*"|[^,"])*){3}),?

1. (?:"[^"]*"|[^,"])*將匹配逗號之間的值（可選，用引號引起來）。 引號被轉義為"" 。

2. (X(?:,X){3}),? 其中X是模式＃1，它將匹配四個逗號分隔值和一個可選尾隨逗號的序列。 逗號必須正確匹配空白值（ ,,foo, ）。

如果保證值始終帶有引號，則可以刪除|[^,"]和,? 。

Answer 4

您可以嘗試使用此正則表達式，但是正則表達式有一個問題：您需要修剪最后一個Comma ，甚至字符串中還有更多的Comma ，而不是4個Comma倍數，它也可以正常工作

string patten = @"(?<=^(?:(?:[^,]*,){4})+)";
string text = @"""T"",""Success"",""2"",""2"",""T"",""Success"",""6458960"",""1"",""F,""You do not have sufficient credit."",""6458962"",""1""";
foreach (var tmp in Regex.Split(text, patten))
{
    Console.WriteLine(tmp.TrimEnd(','));
}

Answer 5

我會避免使用正則表達式，除非您確實需要它，否則通常很難理解。

有趣的是，這里是一個Linq解決方案：

var data = @"""T"",""Success"",""2"",""2"",""T"",""Success"",""6458960"",""1"",""F,""You do not have sufficient credit."",""6458962"",""1""";

var res = data.Split(',')
            .Select((x ,i) => new { Pos = i / 4, Val = x })
            .GroupBy(x => x.Pos)
            .Select(g => string.Join(",", g.Select(x => x.Val)));