方法從陣列

Question

這是什麼PHP腳本相當於C＃語法拿到鑰匙？

<?php 
$arr = array("linux", "windows", "linux", "linux", "windows", "mac os", "unix", "mac os"); 
$unique = array_unique($arr); 
foreach($unique as $key=>$value){ 
    echo $key."\n"; 
} 
?> 

以上代碼的結果是：

0 
1 
5 
6 

因此，數組的副本都刪除，然後顯示數組的鍵。我只能顯示數組的值：

string[] arr = { "linux", "windows", "linux", "linux", "windows", "mac os", "unix", "mac os" }; 
string[] uniq = arr.Distinct().ToArray(); 
foreach (string unik in uniq) 
{ 
    textBox1.AppendText(unik+"\r\n"); 
} 

Answer 1

你可以做到這一點的LINQ很容易：

var indices = arr.Distinct() 
       .Select(s => Array.IndexOf(arr,s)); 

foreach (int i in indices) 
{ 
    textBox1.AppendText(i+"\r\n"); 
} 

，或者包括值和指數：

var indices = arr.Distinct() 
       .Select(s => new {s, i = Array.IndexOf(arr,s)}); 

foreach (var si in indices) 
{ 
    textBox1.AppendText(string.Format({0}: {1}\n", si.i, si.s)); 
} 

如果性能是一個問題，更高效（雖然更難理解）版本將是：

var indices = arr.Select((s, i) => new {s, i}) // select the value and the index 
       .GroupBy(si => si.s)   // group by the value 
       .Select(g => g.First());  // get the first value and index 

foreach (var si in indices) 
{ 
    textBox1.AppendText(string.Format({0}: {1}\n", si.i, si.s)); 
} 

Answer 2

它爲我的作品：

 string[] arr = { "linux", "windows", "linux", "linux", "windows", "mac os", "unix", "mac os" }; 
     string[] uniq = new string[0]; 
     string[] keys = new string[0]; 


     for (int i = 0; i < arr.Length; i++) 
     { 
      if (uniq.Contains(arr[i])) 
      { 
       continue; 
      } 
      else 
      { 
       uniq = uniq.Concat(new string[] { arr[i] }).ToArray(); 
       keys = keys.Concat(new string[] { i + "" }).ToArray(); 
      } 
     } 

     foreach (string key in keys) 
     { 
      textBox1.Append(key + "\r\n"); 
     } 

Answer 3

這裏LINQ的解決方案 - 資源包含了 「ARR」 字符串數組中第一次出現的索引：

string[] arr = { "linux", "windows", "linux", "linux", "windows", "mac os", "unix", "mac os" }; 

var res = arr.Select((value, index) => new { value, index }) 
      .ToDictionary(pair => pair.index, pair => pair.value) 
      .GroupBy(x => x.Value) 
      .Select(x => x.First().Key); 

foreach (int i in res) 
{ 
    textBox1.AppendText(i+"\r\n"); 
}