LSDinterface (version 1.2.2)

select.colattrs.lsd: Select a subset of a LSD results matrix (by variable attributes)

Description

This function select a subset of a LSD results matrix (as produced by read.raw.lsd) by the variable attributes, considering the LSD object position and the time span.

Usage

select.colattrs.lsd( dataSet, info, col.names = NULL, init.value = NA,
                     init.time = NA, end.time = NA, posit = NULL,
                     posit.match = c( "fixed", "glob", "regex" ) )

Value

Returns a single matrix containing the selected variables' time series contained in the original data set.

Arguments

dataSet

matrix produced by the invocation of read.raw.lsd, read.single.lsd, read.multi.lsd or read.list.lsd (a single matrix a time) functions.

info

data frame produced by info.details.lsd for the same results file from where dataSet was extracted.

col.names

a vector of optional names for the variables to select from. The default is to select from all variables.

init.value

initial value attributed to the variable(s) to select.

init.time

initial time attributed to the variable(s) to select.

end.time

end time attributed to the variable(s) to select.

posit

a string, a vector of strings or an integer vector describing the LSD object position of the variable(s) to select. If an integer vector, it should define the position of a SINGLE LSD object. If a string or vector of strings, each element should define one or more different LSD objects, so the returning matrix will contain variables from more than one object. By setting posit.match, globbing (wildcard), and regular expressions can be used to select multiple objects at once; in this case, all matching objects are returned.

posit.match

a string defining how the posit argument, if provided, should be matched against the LSD object positions. If equal to "fixed", the default, only exact matching is done. "glob" allows using simple wildcard characters ('*' and '?') in posit for matching. If posit.match="regex" interpret posit as POSIX 1003.2 extended regular expression(s). See regular expressions for details of the different types of regular expressions. Options can be abbreviated.

Author

Marcelo C. Pereira

Details

Selection restriction arguments can be provided as needed; when not specified, all available cases are selected.

When posit is supplied together with other attribute filters, the selection process is done in two steps. Firstly, the column names set by otter attribute filters are selected. Secondly, the instances defined by posit are selected from the first selection set.

See also the read.XXXX.lsd functions which may select just specific posit object instances when loading LSD results. If only a single set of instances is required, this would be more efficient than using this function.

See Also

list.files.lsd() info.details.lsd(), select.colnames.lsd()

Examples

# get the list of file names of example LSD results
files <- list.files.lsd( system.file( "extdata", package = "LSDinterface" ) )

# read all instances of all variables of first file
bigTable <- read.raw.lsd( files[ 1 ] )

# build the info table
info <- info.details.lsd( files[ 1 ] )

# extract specific instances of a set of variables named '_A1p' and '_growth1'
abFirst2 <- select.colattrs.lsd( bigTable, info, c( "_A1p", "_growth1" ),
                                 posit = c( "1_2", "1_5" ) )
print( abFirst2[ 50 : 60, ] )

# extract instances of variable '_A1p' that start at time step t = 1
# for the second and fourth objects under any top-level object (use globbing)
a24 <- select.colattrs.lsd( bigTable, info, "_A1p", init.time = 1,
                            posit = c( "*_2", "*_4" ), posit.match = "glob" )
print( a24[ 1 : 10, ] )

# extract all second-level object instances of all variables
aSec <- select.colattrs.lsd( bigTable, info, posit = "*_*", posit.match = "glob" )
print( aSec[ 1 : 10, ] )

# extract just top-level object instances variables
aTop <- select.colattrs.lsd( bigTable, info, posit = "^[0-9]+$",
                             posit.match = "regex" )
print( aTop[ 1 : 10, ] )