正則表達式沒有找到

Question

編輯的所有比賽： 我有一個string str = "where dog is and cats are and bird is bigger than a mouse"並希望where和and，and和and，and和句子的末尾之間的提取分離子。結果應該是：dog is,cats are,bird is bigger than a mouse。 （樣本字符串可能包含where和and ECT之間的任何字符串。）

List<string> list = new List<string>(); 
string sample = "where dog is and cats are and bird is bigger than a mouse"; 
MatchCollection matches = Regex.Matches(sample, @"where|and\s(?<gr>.+)and|$"); 
foreach (Match m in matches) 
    { 
    list.Add(m.Groups["gr"].Value.ToString()); 
    } 

但它不工作。我知道正則表達式是不正確的，所以請幫我解決這個問題。謝謝。

Answer 1

使用大括號修復|和回顧後：

using System; 
using System.Text.RegularExpressions; 

public class Solution 
{ 
    public static void Main(String[] args) 
    { 
     string sample = "where dog is and cats are and bird is bigger than a mouse"; 
     MatchCollection matches = Regex.Matches(sample, @"(?<=(where|and)\s)(?<gr>.+?)(?=(and|$))"); 
     foreach (Match m in matches) 
     { 
      Console.WriteLine(m.Value.ToString()); 
     } 
    } 
} 

小提琴：https://dotnetfiddle.net/7Ksm2G

輸出：

dog is 
cats are 
bird is bigger than a mouse 

Answer 2

如何"\w+ is"

List<string> list = new List<string>(); 
string sample = "where dog is and cat is and bird is"; 
MatchCollection matches = Regex.Matches(sample, @"\w+ is"); 
foreach (Match m in matches) 
{ 
    list.Add(m.Value.ToString()); 
} 

樣品：https://dotnetfiddle.net/pMMMrU

Answer 3

您應該使用Regex.Split()方法不Regex.Match()。

string input = "where dog is and cats are and bird is bigger than a mouse"; 
    string pattern = "(?:where|and)"; 
    string[] substrings = Regex.Split(input, pattern); 
    foreach (string match in substrings) 
    { 
     Console.WriteLine("'{0}'", match); 
    } 

這將分裂的文字的話where和and。

Ideone Demo