Construct a lazy view over an array source — source

A view stores its selectors in the package's normalized selection form rather than as expanded position vectors: a select-all axis stores no vector, one contiguous run stores its bounds, and only an arbitrary subset stores positions. A view over a view composes into one view over the root source. Selectors follow the package-wide normalization law: logical masks must match the axis length without NA; numeric positions must be whole numbers, may reorder, may be negative (but not mixed with positive), drop zero, must be in bounds, and may not repeat an element; an empty selection is legal. Fingerprints hash the normalized form, so equal selections agree however they were expressed and a select-all view fingerprints in constant time.

Usage

source_view(source, observations = NULL, features = NULL)

Arguments

source: An array_source.
observations: Stored observation selector.
features: Stored feature selector.

Value

A serializable source view.

Examples

src <- memory_source(matrix(seq_len(6), nrow = 2))
view <- source_view(src, observations = 1)
source_shape(view)
#> [1] 1 3