Editing Sparse matrix (section)

===Dictionary of keys (DOK)===

DOK consists of a [[associative array|dictionary]] that maps {{math|(row, column)}}-[[ordered pair|pairs]] to the value of the elements. Elements that are missing from the dictionary are taken to be zero. The format is good for incrementally constructing a sparse matrix in random order, but poor for iterating over non-zero values in lexicographical order. One typically constructs a matrix in this format and then converts to another more efficient format for processing.<ref>See [http://docs.scipy.org/doc/scipy/reference/generated/scipy.sparse.dok_matrix.html <code>scipy.sparse.dok_matrix</code>]</ref>