唯一名稱給定列表和種子

Question

我的問題是在由'種子'組成的列表中生成一個新的唯一名稱，使用相同的種子重複使用缺少的索引。

我寫下了下面的擴展

/// <summary> 
    /// Gets the Next Valid Index given a list of names and a root string. 
    /// </summary> 
    /// <param name="names">The list of just used names.</param> 
    /// <param name="seedName">The string to be used as seed.</param> 
    /// <returns>System.Int32 (One Based) with next valid Index.</returns> 
    /// <Examble> 
    /// Present Names: 
    /// AA, AA1, AA2, BB, BB3 
    /// With Seed AA, result is 3 
    /// With Seed BB, result is 1 
    /// With Seed CC, result is 1 (missing index is used) 
    /// </Examble> 
    public static int GetNextIndex(this List<string> names, string seedName) 
    { 
     var max = 0; 
     var namesIndexes = new List<NameIndex>(); 

     names.ForEach(name => 
     { 
      var m = Regex.Match(name, @"\d+"); 
      if (m.Success) 
      { 
       if (string.IsNullOrWhiteSpace(m.Value)) 
       { 
        namesIndexes.Add(new NameIndex(name, 0)); 
       } 
       else 
       { 
        var v = 0; 
        if (int.TryParse(m.Value, out v)) 
         namesIndexes.Add(new NameIndex(name.Replace(m.Value, string.Empty), v)); 
       } 
      } 
      else 
      { 
       namesIndexes.Add(new NameIndex(name, 0)); 
      } 
     }); 

     var grouped = namesIndexes.GroupBy(n => n.Name).ToDictionary(g => g.Key, g => g); 
     if (grouped.ContainsKey(seedName)) 
     { 
      max = grouped[seedName].Max(gn => gn.Index); 
      var all = Enumerable.Range(1, max).ToList(); 
      var available = all.Except(grouped[seedName].Select(gn => gn.Index)).ToList(); 
      if (available.Any()) 
       return available.Min(); 
     } 

     return max + 1; 
    } 

凡NameIndex是一個輔助類：

/// <summary> 
/// Class NameIndex. 
/// </summary> 
public class NameIndex 
{ 
    public string Name { get; set; } 
    public int Index { get; set; } 

    public NameIndex(string name, int index) 
    { 
     Name = name; 
     Index = index; 
    } 
} 

我的問題是：你如何改進功能？

感謝您的幫助！

Answer 1

看是否有此代碼對你的作品

public static int GetNextIndex(List<string> names, string seedName) 
{ 
    var namesWithSeed = names.Where(n => !string.IsNullOrEmpty(n) && n.StartsWith(seedName)); 
    if (names.Count == 0) 
     return 1; 
    int temp = 0; 
    var allIntsStringsForSeed = namesWithSeed 
           .Select(n => n.Replace(seedName, string.Empty)) 
           .Select(s => int.TryParse(s, out temp) ? temp : 0) 
           .OrderBy(i => i) 
           .ToList(); 
    var idx = 0; 
    for (int i = 0; i < allIntsStringsForSeed.Count; i++) 
    { 
     if (i == allIntsStringsForSeed.ElementAt(i)) 
      idx = i; 
     else 
      break; 
    } 
    return idx == 0 ? 1 : idx + 1; 
} 

測試

var strings = new List<string> { "AA", "AA1", "AA2", "BB", "BB3" }; 
var indexAA = GetNextIndex(strings, "AA"); //3 
var indexBB = GetNextIndex(strings, "BB"); //1 
var indexCC = GetNextIndex(strings, "CC"); //1