sparsearray2d

Description:

sparsearray2d

A fast and flexible generic sparse 2 dimensional array.
Features #

Exposes graph such that clients may easily walk directly between neighbouring elements to allow fast array traversal.
Easy conversion between dense and sparse formats.

Usage #
Example:
final sparse = SparseArray2D<String>();

sparse.put(2, 0, 'a');
sparse.put(2, 1, 'b');
sparse.put(2, 5, 'c');
sparse.put(2, 8, 'd');
sparse.put(0, 5, 'e');

print('Sparse form elements');
print(sparse.sparseRows.join('\n'));

print('Dense form values');
print(sparse.denseRows.join('\n'));

print('Dense form with default value "_"');
print(sparse.denseRows.map((final row) => row.padded('-')).join('\n'));

print('Extract row as sparse elements');
print(sparse.sparseRowAt(2));

print('Extract row as sparse values with default value "*"');
print(sparse.sparseRowAt(2)!.dense.padded('*'));

print('Extract column as sparse elements');
print(sparse.sparseColumnAt(5)!.join('\n'));

print('Extract column as sparse values with default value "*"');
print(sparse.sparseColumnAt(5)!.dense.padded('*').join('\n'));

copied to clipboard
Output:
Sparse form elements
(0)[(0, 5)[e]]
(2)[(2, 0)[a],(2, 1)[b],(2, 5)[c],(2, 8)[d]]

Dense form values
(null, null, null, null, null, e, null, null, null)
(null, null, null, null, null, null, null, null, null)
(a, b, null, null, null, c, null, null, d)

Dense form with default value "_"
(-, -, -, -, -, e, -, -, -)
(-, -, -, -, -, -, -, -, -)
(a, b, -, -, -, c, -, -, d)

Extract row as sparse elements
(2)[(2, 0)[a],(2, 1)[b],(2, 5)[c],(2, 8)[d]]

Extract row as sparse values with default value "*"
(a, b, *, *, *, c, *, *, d)

Extract column as sparse elements
(0, 5)[e]
(2, 5)[c]

Extract column as sparse values with default value "*"
e
*
c
copied to clipboard