title: How to combine multiple string list with separator
body: <p>I have three string list, the purpose is combine these list to a single string with separator.</p>
  
  <pre><code>List&lt;string&gt; list1=new List&lt;string&gt;{"A","B","C"};
  List&lt;string&gt; list2=new List&lt;string&gt;{"=","&lt;", "&gt;"};
  List&lt;string&gt; list3=new List&lt;string&gt;{"1","2","3"};
  </code></pre>
  
  <p>The final output is like following:</p>
  
  <pre><code>A=1 AND B&lt;2 AND C&gt;3
  </code></pre>
  
  <p>Is there any easy way to generate the final string? I used for loop, but it seems to be ugly. I know C# string has <code>Join</code> method to combine an array with separator. How to combine multiple arrays with separator?</p>
  
  <p>Below is my code:</p>
  
  <pre><code>StringBuilder str = new StringBuilder();
  for(int i=0; i&lt; list1.count; i++)
  {
      str.AppendFormat("{0}{1}{2} AND ", list1[i], list2[i], list3[i]);
  }
  str.Length = str.Length -5;
  string final = str.ToString();
  </code></pre>