c# - 从字典<>中以文化不变/大小写不变的方式寻找值(value)<>

Question

如果我有这样的字典

Dictionary<string, List<string>> cars = new Dictionary <string,List<string>>();

'importcar',    ['audi', 'bmw', 'mercedes']
'domesticcar',  ['chevy', 'mustang']
'truck',        ['ford', 'gmc', 'chevy', 'toyota']

如何检查此字典的列表值中是否包含字符串？

对于上面的例子，我如何在 InvariantCulture 和 Ignored 的情况下检查这个字典是否有字符串 'chevy'(在上面的例子中，它有键 'domesticcar' 和 'truck')？

我试过了，虽然它有效，但它似乎并不优雅

// this will search for a car in dictionary under any key and find 1st occurance of it
// of it and remove it.  If List for the key is empty, it will remove the key as well.
foreach (var k in cars.Keys)
{
  bool found = false;

  List<string> ls = cars[k];  // get List for key
  if (ls.Contains("chevy", StringComparer.InvariantCultureIgnoreCase))
  {
    // get first occurance of car and remove it if found in list
    var car = ls.FirstOrDefault(c => c.Trim().ToLowerInvariant() == "chevy".Trim().ToLowerInvariant());
    if (car != null)
    {
      found = true;  //found 1st occurance of car in Dictionary, flag to exit loop
        ls.Remove(car);
    }
  }
  // remove key if its List<string> is empty
  if (ls.Count == 0)
  {
    cars.Remove(k);
  }

  if (found) break;
}

Answer 1

你可以这样使用contains:

var keys = cars.Where(c => c.Value.Contains("chevy", StringComparer.InvariantCultureIgnoreCase)).Select(a => a.Key);

//编辑:我得到了反对票？当然你可以使用修剪:

public static IEnumerable<string> GetKeys(Dictionary<string, List<string>> storage, string car)
{
    return storage.Where(c => c.Value.Contains(car.Trim(), StringComparer.InvariantCultureIgnoreCase)).Select(a => a.Key);
}