Calculating/Averaging over a struct value

[Jesse Phillips]

On Wednesday, 21 March 2012 at 20:13:37 UTC, Jesse Phillips wrote:

> Note, I commented out reduce as it uses the array type instead 
> of the calculation type. I think I'll file than as a bug. Also 
> the reduce version would not give you a double back even if it 
> did work, need a cast in there.

Nevermind, just needed to map

double average(string param)(Data[] x)
{
  static if (!isNumeric!(typeof(mixin("Data."~param))))
    return -1;
  else
  {
   return cast(double)reduce!("a + 
b")(map!("a."~param)(x))/x.length;
  }
}