R: Extracts a vector from the Data Base

db.extract {RGeostats}

R Documentation

Extracts a vector from the Data Base

Description

Extracts a vector from the db-class

Usage

db.extract(db, names, flag.compress = TRUE, flag.2d=FALSE, flag.log10=FALSE,
	pos.x=1, pos.y=2, ref = NA, flag.ignore.sel=FALSE)

Arguments

`db`	`db-class` from which a vector must be extracted
`names`	List of names of the attributes which must be extracted. For more information see `db.ident`.
`flag.compress`	If TRUE, the function only returns the values corresponding to the active samples (not masked by the current selection). Otherwise, values are returned for all the samples.
`flag.2d`	If TRUE (and if the `db-class` is a Grid Db), only a 2-D plane of the grid is output. The definition of this plane is given by next arguments
`flag.log10`	If TRUE, the extracted vector is log-transformed (base 10). The negative values are turned into NA.
`pos.x`	Gives the rank of the coordinate used on the abscissae axis. Used only if flag.2d = TRUE.
`pos.y`	Gives the rank of the coordinate used on the ordinate axis. Used only if flag.2d = TRUE
`ref`	Vector (of space dimension) which gives the indices of the reference corner point. The extracted plane contains the reference corner point. Used only if flag.2d = TRUE.
`flag.ignore.sel`	When TRUE, this extraction is performed ignoring any possible selection.

Value

The vector of values. Its length is equal to the total number of samples (if flag.compress=FALSE) or to the number of active samples otherwise. If the number of fields to be extracted is equal to 1, the result is a list of values, whereas it will be a data.frame when extracting more than 1 field.

Examples

data(Z_data.db) # Load the Documentation Points Db
Z_data.db # Print a short contents of the Db

# Extract the vectors which corresponds to variables 'z1' and 'z2' #
vector <- db.extract(Z_data.db,names=c("z1","z2"))
vector # Print the contents of the extracted vector #

# Clean up
rm(Z_data.db,vector)