Round brackets can be used to index into Array, Matrix, and Vector data structures.  For full details refer to ?rtable_indexing. Highlights include:

the ability to grow arrays past their initially declared bounds.

the ability to reference multi-dimensional arrays with a single integer, making looping over all elements easier and more efficient.

compatibility with the way MATLAB® indexes arrays.

The zip command now accepts a prefix option: zip[sparse], and zip[dense] indicating whether the zeros in the sparse objects should be ignored or included.

zip[sparse]((x,y)->x+y+1,Array(1..3,{1=1},storage=sparse),
    Array(1..4,{2=2},storage=sparse));

$\left[\begin{array}{ccc}2& 3& 0\end{array}\right]$

zip[dense]((x,y)->x+y+1,Array(1..3,{1=1},storage=sparse),
    Array(1..4,{2=2},storage=sparse));

$\left[\begin{array}{ccc}2& 3& 1\end{array}\right]$

The max and min commands now accept lists and rtable-based arrays as arguments.  The list or array is scanned to find the maximum or minimum object contained inside.

max( [-5,1,17], <12,-32,4> );

$17$

min( <12,-32,4> );

$\mathrm{-32}$