There are probably people here who can give a better answer than me. There are *certainly* people on the PDL mailing list who can provide a better answer than I can.

As a quick stab, you could try at():

pdl> help at
Module  PDL::Core
  at
    Returns a single value inside a piddle as perl scalar.

     $z = at($piddle, @position); $z=$piddle->at(@position);

    @position is a coordinate list, of size equal to the number of
    dimensions in the piddle. Occasionally useful in a general context
+,
    quite useful too inside PDL internals.

     pdl> $x = sequence 3,4
     pdl> p $x->at(1,2)
     7

    at converts any bad values into the string 'BAD'.

    # line 3108 "Basic/Core/Core.pm.PL (i.e. PDL::Core.pm)"

pdl>
[download]

but I don't know if that's the best option.

Cheers,
Rob