This is documentation for Mathematica 5, which was
based on an earlier version of the Wolfram Language.

 SparseArray SparseArray[->, ->, ... ] yields a sparse array in which values appear at positions . SparseArray[, , ... ->, , ... ] yields the same sparse array. SparseArray[list] yields a sparse array version of list. SparseArray[data, , , ... ] yields a sparse array representing a array. SparseArray[data, dims, val] yields a sparse array in which unspecified elements are taken to have value val. By default, SparseArray takes unspecified elements to be 0. SparseArray[data, ... ] is always converted to an optimized standard form with structure SparseArray[Automatic, dims, val, ... ]. Normal[SparseArray[... ]] gives the ordinary array corresponding to a sparse array object. ArrayRules[SparseArray[... ]] gives the list of rules ->, ->, ... . The elements in SparseArray need not be numeric. The position specifications can contain patterns. Example: SparseArray[i_, i_->1, d, d] gives a identity matrix. With rules :> the are evaluated separately for each set of indices that match . SparseArray[list] requires that list be a full array, with all parts at a particular level being lists of the same length. The individual elements of a sparse array cannot themselves be lists. SparseArray[rules] yields a sparse array with dimensions exactly large enough to include elements whose positions have been explicitly specified. SparseArray[rules, Automatic, val] takes unspecified elements to have value val. List and matrix operations are typically set up to work as they do on Normal[SparseArray[... ]]. Functions with attribute Listable are automatically threaded over the individual elements of the ordinary arrays represented by SparseArray objects. Part extracts specified parts of the array represented by a SparseArray object, rather than parts of the SparseArray expression itself. Functions like Map are automatically applied to components in a SparseArray object. SparseArray is treated as a raw object by functions like AtomQ, and for purposes of pattern matching. Dimensions gives the dimensions of a sparse array. The standard output format for a sparse array specified by n rules is SparseArray[, dims]. See Section 2.4.1 and Section 2.4.5. Implementation Notes: see Section A.9.4. See also: ArrayRules, Normal, Replace. New in Version 5.0.