问提取3-8位数字和3个字母文本(级联文本)之间的数据的Regex。

EN

var pattern = @"(?<=\d{3,8}\s).*(?=\s[A-Z]{3})";

var input = @"06/29/20 B QM 02004946 MY HELLO WORLD XLS
08/29/20 B QM 0948264 MY UI PATH LMN
08/29/20 B QM 435 MY SAMPLE DATA LMN
06/29/20 B QM 123 MY HELLO WORLD XLS";

var results = Regex
       .Matches(input, pattern, RegexOptions.Multiline)
       .Cast<Match>()
       .Select(x => x.Value);

Console.WriteLine(string.Join(", ", results));

MY HELLO WORLD, MY UI PATH, MY SAMPLE DATA, MY HELLO WORLD

(?<=\d{3,8}\s).*(?=\s[A-Z]{3}$)

var pattern = @"(?<=\d{3,8}\s).*(?=\s[A-Z]{3}$)";

var strings = new List<string>()
{
   "06/29/20 B QM 02004946 MY HELLO WORLD XLS",
   "08/29/20 B QM 0948264 MY UI PATH  LMN",
   "08/29/20 B QM 435 MY SAMPLE DATA   LMN"
};

var results = strings.Select(x => Regex.Match(x, pattern).Value);

foreach (var result in results)
   Console.WriteLine(result);

MY HELLO WORLD
MY UI PATH
MY SAMPLE DATA