SparseArray

SparseArray[{pos1 -> v1, pos2 -> v2, ...}] yields a sparse array with values at specified positions.

SparseArray[list] yields a sparse array version of list.

SparseArray[data, dims, val] uses val for unspecified elements.

Examples

Create a sparse array with specific values:

SparseArray[{{1, 1} -> 1, {2, 2} -> 2, {3, 3} -> 3}]
(* SparseArray[..., {3, 3}] *)

Convert to normal array:

Normal[SparseArray[{{1, 1} -> 1, {2, 2} -> 1}, {2, 2}]]
(* {{1, 0}, {0, 1}} *)

Please visit the official Wolfram Language Reference for more details.