# calculate the number of elements in each chunk
pdl> $idx = ($b/5)->floor
pdl> $idx -= ($b - $idx * 5) == 0

pdl> p [$qidx->hist(-1,4,1)]->[1]
[1 5 5 9 0]

##</code><code>##

pdl> p pdl($a(($b>0)*($b<=5);?)->medover, $a(($b>5)*($b<=10);?)->medover, $a(($b>10)*($b<=15);?)->medover)
[7 8 11]


##</code><code>##

pdl> $start = 0;
pdl> $step = 5;
pdl> $d = pdl(  map { $a(($b > $start + $step *$_ )*( $b <= $start + $step*($_+1) );?)->medover } 0..3 )
pdl> p $d
[7 8 11 13]