mapcar { push @{$facdata{$_[0])}, $_[1] } \@facfields, \@facrow;

##</code><code>##

    for( 0..$#facfields ) {
        push @{ $facdata{$facfields[$_]} }, $facrow[$_];
    }
# or
    push @{ $facdata{$_} }, shift @facrow  for @facfields;