如何比較兩個字符串數組並找到公共字符串數組的索引號並將其應用於第三個字符串數組？

Question

我有三個字符串數組

string[] stringArray= {"AAA", "BBB", "CCC","DDD", "EEE","FFF","GGG","HHH" };
string[] stringArray1 = { "A", "B", "C","D", "E","F","G","H" };
string[] stringArray2 = { "BBB", "DDD","FFF","HHH" };

我怎樣才能將stringArray2與stringArray進行比較，並找到匹配的索引號stringArray 。 找到索引后，我需要將它應用於stringArray1並顯示結果。

我嘗試了以下代碼，但未能獲得匹配字符串

int j=0;
string line = null;
List<string> finalstring = new List<string>();

for (int i = 0; i < stringArray.Count; i++)
{ 
   while(stringArray[i] == stringArray2[j])
   {
      line = stringArray2[i];
      finalstring.Add(line);
      j++;
   }
}

Answer 1

我想你必須這樣試試：

var result = stringArray1.Where(c => // iterating stringArray1
             stringArray2.Where(x => stringArray.Contains(x)) // filtering stringArray2 elements
                         .Any(y=>y.Contains(c))).ToList(); // collect the final result

一個工作示例供您參考

Answer 2

int j=0;
string line = null;
List<string> finalstring = new List<string>();
for (int i = 0; i < stringArray.Length; i++)
//for (int i = 0; i < stringArray.Count; i++)   // <-- Count is not proper way to get total elements in an array
{
   j = 0;  // <-- you failed to reinitialize 'j' 
   //while(stringArray[i] == stringArray2[j])  // <-- while is not proper way to compare
   if(stringArray[i] == stringArray2[j])
   {
      //line = stringArray2[i];

      //if only first charracter is needed
      finalstring.Add(new string(stringArray2[i][0], 1));

      //if complete string is needed
      //finalstring.Add(stringArray2[i]);

      j++;
   }
}

以上不是進行比較的優化方法。 您可以嘗試使用HashSet類

    string[] stringArray= {"AAA", "BBB", "CCC","DDD", "EEE","FFF","GGG","HHH" };
    string[] stringArray1 = { "A", "B", "C","D", "E","F","G","H" };
    string[] stringArray2 = { "BBB", "DDD","FFF","HHH" };

    //convert string array to hashset
    var hashSet = new HashSet<string>(stringArray);

    int j=0;
    string line = null;
    List<string> finalstring = new List<string>();

    for (int i = 0; i < stringArray2.Length; i++)
    {
        if(hashSet.Contains(stringArray2[i]))
        {
            //if only first charracter is needed
            finalstring.Add(new string(stringArray2[i][0], 1));
        }
    } 

Answer 3

List<string> finalList = new List<string>();
stringArray.Select((value,index) => new { value, index })
.Where(num => stringArray2.Contains(num.value)).ToList()
.ForEach(num => finalList.Add(stringArray1[num.index]));

Answer 4

您正在嘗試比較相同索引上的元素，但您必須在stringArray搜索stringArray2的元素。 您可以使用Array.IndexOf在Array中查找所需的元素。

string[] stringArray= {"AAA", "BBB", "CCC","DDD", "EEE","FFF","GGG","HHH" };
string[] stringArray1 = { "A", "B", "C","D", "E","F","G","H" };
string[] stringArray2 = { "BBB", "DDD","FFF","HHH" };
    int j=0;
string line = null;
List<string> finalstring = new List<string>();

for (int i = 0; i < stringArray2.Count(); i++)
{ 
   if(Array.IndexOf(stringArray, stringArray2[i]) != -1)
   {
      int idx = Array.IndexOf(stringArray1, stringArray2[i][0].ToString());
      if(idx!=-1)
        finalstring.Add(stringArray1[idx]);
    }  
}

使用Linq 編輯

var result2 = stringArray1.Where(c=>
              stringArray2.Intersect(stringArray)
              .Any(i=>i.Contains(c)));

Answer 5

你可以通過Linq選擇索引（ where >= 0過濾掉所有非匹配）：

string[] stringArray = { "AAA", "BBB", "CCC", "DDD", "EEE", "FFF", "GGG", "HHH" };
string[] stringArray1 = { "A", "B", "C", "D", "E", "F", "G", "H" };
string[] stringArray2 = { "BBB", "DDD", "FFF", "HHH" };

var matches = stringArray2
    .Select(s => Array.FindIndex(stringArray, s2 => s2 == s))
    .Where(i => i >= 0).Select(i => stringArray1[i])
    .ToList();

這是一個dotnetfiddle