code: function select(expression) {
  
          //Check arguments
          if (!expression)
              throw new Error("Expression is invalid");
  
          //Data for output
          var outData = [];
  
          //For each element on items
          for (var i = 0; i < this.items.length; i++) {
  
              //Invoke expression and obtain element
              var result = expression(this.items[i]);
  
              //Append to out list
              outData.push(result);
          }
  
          //Return for chaining
          return new jslinq(outData);
      }
docs: #region "select" Select clause