fromDataFrame: Create a TileDB dense or sparse array from a given...

In tiledb: Modern Database Engine for Complex Data Based on Multi-Dimensional Arrays

Create a TileDB dense or sparse array from a given data.frame Object

Description

The supplied data.frame object is (currently) limited to integer, numeric, or character. In addition, three datetime columns are supported with the R representations of Date, POSIXct and nanotime.

Usage

fromDataFrame(
  obj,
  uri,
  col_index = NULL,
  sparse = TRUE,
  allows_dups = sparse,
  cell_order = "COL_MAJOR",
  tile_order = "COL_MAJOR",
  filter = "ZSTD",
  capacity = 10000L,
  tile_domain = NULL,
  tile_extent = NULL,
  mode = c("ingest", "schema_only", "append"),
  filter_list = NULL,
  coords_filters = "ZSTD",
  offsets_filters = "ZSTD",
  validity_filters = "RLE",
  debug = FALSE,
  timestamps = as.POSIXct(double(), origin = "1970-01-01")
)

Arguments

obj	A data.frame object.
uri	A character variable with an Array URI.
col_index	An optional column index, either numeric with a column index, or character with a column name, designating an index column; default is NULL implying an index column is added when the array is created
sparse	A logical switch to select sparse (the default) or dense
allows_dups	A logical switch to select if duplicate values are allowed or not, default is the same value as ‘sparse’.
cell_order	A character variable with one of the TileDB cell order values, default is “COL_MAJOR”.
tile_order	A character variable with one of the TileDB tile order values, default is “COL_MAJOR”.
filter	A character variable vector, defaults to ‘ZSTD’, for one or more filters to be applied to each attribute;
capacity	A integer value with the schema capacity, default is 10000.
tile_domain	An integer vector or list or NULL. If an integer vector of size two it specifies the integer domain of the row dimension; if a list then a named element is used for the dimension of the same name; or if NULL the row dimension of the obj is used.
tile_extent	An integer value for the tile extent of the row dimensions; if NULL the row dimension of the obj is used. Note that the tile_extent cannot exceed the tile domain.
mode	A character variable with possible values ‘ingest’ (for schema creation and data ingestion, the default behavior), ‘schema_only’ (to create the array schema without writing to the newly-created array) and ‘append’ (to only append to an already existing array).
filter_list	A named list specifying filter choices per column, default is an empty list object. This argument applies for all named arguments and the matchin dimensions or attributes. The filter argument still applies for all unnamed arguments.
coords_filters	A character vector with filters for coordinates, default is ZSTD.
offsets_filters	A character vector with filters for coordinates, default is ZSTD.
validity_filters	A character vector with filters for coordinates, default is RLE.
debug	Logical flag to select additional output.
timestamps	Vector with up to two POSIXct variables denoting open intervals; default is length zero where start and end are set (implicitly) to current time; in case of one value it is used as the interval end, and in case of two values they are taken as start and end. This applies to write and append modes only and not to schema creation.

Details

The created (dense or sparse) array will have as many attributes as there are columns in the data.frame. Each attribute will be a single column. For a sparse array, one or more columns have to be designated as dimensions.

At present, factor variable are converted to character.

Value

Null, invisibly.

Examples

uri <- tempfile()
fromDataFrame(iris, uri)
arr <- tiledb_array(uri, return_as="data.frame", extended=FALSE)
newdf <- arr[]
all.equal(iris, newdf, check.attributes=FALSE)  # extra attribute on query in newdf
all.equal(as.matrix(iris), as.matrix(newdf))	# also strips attribute

tiledb documentation built on Oct. 4, 2024, 5:06 p.m.