• Dimensions[expr] gives a list of the dimensions of expr.
• Dimensions[expr, n] gives a list of the dimensions of expr down to level n.
• expr must be a full array, with all the pieces of expr at a particular level having the same length. (The elements of expr can then be thought of as filling up a hyper-rectangular region.)
• Each successive level in expr sampled by Dimensions must have the same head.
• For SparseArray
yields the dimensions of the corresponding ordinary lists.
• New in Version 1; modified in 5.