是否有一种方法可以覆盖类型Regex
的变量的值?
我有如下工作代码:
string[] dirEntries = Directory.GetFiles(inputDir, "*.csv", SearchOption.TopDirectoryOnly);
var fileList = dirEntries
.Select(x => new FileMetaDto
{
FileName = Path.GetFileName(x),
FullPath = x,
FileType = fileType,
});
switch (fileType)
{
case "pd": // probability of default
Regex myRegexPD = new Regex("^PD_"); // probability of default
fileList = fileList.Where(x => myRegexPD.IsMatch(x.FileName));
break;
case "fx": // exchange rate
Regex myRegexFx = new Regex("^FX_"); // exchange rate
fileList = fileList.Where(x => myRegexFx.IsMatch(x.FileName));
break;
default:
System.Diagnostics.Debug.WriteLine("File type not valid.");
break;
}
实际上,这个switch
语句要长得多,所以我想通过做以下事情来缩短事情:
my Regex myRegex = new Regex();
switch (fileType)
{
case "pd":
myRegex = "^PD_";
break;
case "fx":
myRegexFx = "^FX_";
break;
default:
System.Diagnostics.Debug.WriteLine("File type not valid.");
myRegEx = "*";
break;
}
fileList = fileList.Where(x => myRegex.IsMatch(x.FileName));
但是,这会导致各种类型转换错误。有什么建议解决这个问题吗?
答案 0 :(得分:4)
我建议将模式组织到 dictionary 中,并摆脱switch ... case
:
//TODO: I've hardcoded the patterns, but you may well want to generate them:
// s_Patterns = MyFileTypes.ToDictionary(t => t.Name, $"^{t.Name.ToUpper()}_");
private static Dictionary<string, string> s_Patterns = new Dictionary<string, string>() {
{"pd", "^PD_"},
{"fx", "^FX_"},
};
然后您可以轻松使用它们:
if (s_Patterns.TryGetValue(fileType, out var pattern))
fileList = fileList.Where(x => Regex.IsMatch(x.FileName, pattern));
else
System.Diagnostics.Debug.WriteLine("File type not valid.");