var arr = [ "one", "two", "three", "four"];    
$.each(arr, function(){    
  alert(this);    
 });   
 //上面这个each输出的结果分别为：one,two,three,four

public static T[] Each<T>(T[] source, Func<T, T> function)
{

  T[] ret =new T[source.Length];
  int i = 0;
  foreach (T item in source)
  {
    ret[i]=function(item);
    i++;
  }
  return ret;
}　

var arr =new string[]{ "one", "two", "three", "four"};   
 var newArr= ListEx.Each<string>(arr,delegate(string x){
   x=x+"_do";
  return x;
 });

 var newArr2 = ListEx.Each<string>(newArr, (string x) => x = x + "_do");

public static IList<T> Find<T>(IList<T> source, Predicate<T> predicate)
{
  List<T> ret = new List<T>();
  foreach (T item in source)
  {
    if (predicate(item))
    {
      ret.Add(item);
    }
  }
  return ret;
}
public static T[] Where<T>(T[] source, Predicate<T> predicate)
{
  IList<T> list=source.ToList<T>();
  IList<T> retList= Find<T>(list, predicate);
  return retList.ToArray<T>();
}

var newArr3 = ListEx.Where<string>(arr, x => x == "two");