string test = "Abcccccc";
Regex reg = new Regex("abc");
Console.WriteLine(reg.IsMatch(test)); //false
Regex reg1 = new Regex("abc",RegexOptions.IgnoreCase); //不區(qū)分大小寫
Console.WriteLine(reg1.IsMatch(test));//true

string test = "vvv123===456vvv";
Regex reg = new Regex("\\d+");// 123  從左到右 匹配連續(xù)數(shù)字
Console.WriteLine(reg.Match(test));
Regex reg1 = new Regex("\\d+",RegexOptions.RightToLeft);
Console.WriteLine(reg1.Match(test));// 456 從右到左 匹配連續(xù)數(shù)字

StringBuilder input = new StringBuilder();
input.AppendLine("A bbbb A");
input.AppendLine("C bbbb C");

string pattern = @"^\w";
Console.WriteLine(input.ToString());
MatchCollection matchCol = Regex.Matches(input.ToString(), pattern, RegexOptions.Multiline);
foreach (Match item in matchCol)
{
  Console.WriteLine("結(jié)果：{0}", item.Value);
}

Regex.Matches(input.ToString(), pattern, RegexOptions.IgnoreCase | RegexOptions.Multiline);