如何获取C＃Regex中捕获的组的名称？

Question

有没有办法在C＃中获取捕获的组的名称？

string line = "No.123456789 04/09/2009 999"; 
Regex regex = new Regex(@"(?<number>[\d]{9}) (?<date>[\d]{2}/[\d]{2}/[\d]{4}) (?<code>.*)"); 

GroupCollection groups = regex.Match(line).Groups; 

foreach (Group group in groups) 
{ 
    Console.WriteLine("Group: {0}, Value: {1}", ???, group.Value); 
} 

我想要得到这样的结果：

 
Group: [I don´t know what should go here], Value: 123456789 04/09/2009 999 
Group: number, Value: 123456789 
Group: date, Value: 04/09/2009 
Group: code, Value: 999 

Answer 1

使用GetGroupNames获得组列表中的表达式，然后遍历这些，使用的名称作为关键字为组集合。

例如，

GroupCollection groups = regex.Match(line).Groups; 

foreach (string groupName in regex.GetGroupNames()) 
{ 
    Console.WriteLine(
     "Group: {0}, Value: {1}", 
     groupName, 
     groups[groupName].Value); 
} 

Answer 2

您应该使用GetGroupNames();，代码会是这个样子：

string line = "No.123456789 04/09/2009 999"; 
    Regex regex = 
     new Regex(@"(?<number>[\d]{9}) (?<date>[\d]{2}/[\d]{2}/[\d]{4}) (?<code>.*)"); 

    GroupCollection groups = regex.Match(line).Groups; 

    var grpNames = regex.GetGroupNames(); 

    foreach (var grpName in grpNames) 
    { 
     Console.WriteLine("Group: {0}, Value: {1}", grpName, groups[grpName].Value); 
    } 

Answer 3

做到这一点，最彻底的方法是使用这个扩展方法：

public static class MyExtensionMethods 
{ 
    public static Dictionary<string, string> MatchNamedCaptures(this Regex regex, string input) 
    { 
     var namedCaptureDictionary = new Dictionary<string, string>(); 
     GroupCollection groups = regex.Match(input).Groups; 
     string [] groupNames = regex.GetGroupNames(); 
     foreach (string groupName in groupNames) 
      if (groups[groupName].Captures.Count > 0) 
       namedCaptureDictionary.Add(groupName,groups[groupName].Value); 
     return namedCaptureDictionary; 
    } 
} 

一旦这种扩展方法我你可以得到像这样的名称和值：

var regex = new Regex(@"(?<year>[\d]+)\|(?<month>[\d]+)\|(?<day>[\d]+)"); 
    var namedCaptures = regex.MatchNamedCaptures(wikiDate); 

    string s = ""; 
    foreach (var item in namedCaptures) 
    { 
     s += item.Key + ": " + item.Value + "\r\n"; 
    } 

    s += namedCaptures["year"]; 
    s += namedCaptures["month"]; 
    s += namedCaptures["day"]; 

Answer 4

正则表达式类是这个关键！

foreach(Group group in match.Groups) 
{ 
    Console.WriteLine("Group: {0}, Value: {1}", regex.GroupNameFromNumber(group.Index), group.Value); 
} 

http://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex.groupnamefromnumber.aspx

Answer 5

由于.NET 4.7，有Group.Name财产available。