subset: extract a subset of a colorSpec Object

In colorSpec: Color Calculations with Emphasis on Spectral Data

extract a subset of a colorSpec Object

Description

extract a subset of the spectra in a colorSpec object.
The subset can be specified by indexes, by a logical vector, or by a regular expression matching the specnames

Usage

## S3 method for class 'colorSpec'
subset( x, subset, ... )

Arguments

x	a colorSpec object
subset	an integer vector, a logical vector, or a regular expression
...	additional arguments ignored

Details

If subset is an integer vector, each integer must be between 1 and M, where M the number of spectra in x. No duplicates are allowed. The number of spectra returned is equal to length(subset). It is OK for the length to be 0, in which case the function returns the empty subset.

If subset is a logical vector, its length must be equal to M. The number of spectra returned is equal to the number of TRUEs in subset.

If subset is a regular expression, the number of spectra returned is equal to the number of specnames(x) matched by the expression.

Value

subset(x) returns a colorSpec object with the same organization as x. Exception: if the organization of x is 'vector' and the subset is empty, then the returned object is a matrix with 0 columns.

Note

subset() can also be used for re-ordering the spectra; just set argument subset to the desired permutation vector.

See Also

organization

Examples

tritanope = subset( lms2000.1nm, 1:2 )  # keep long and medium cone fundamentals, but drop the short

sml2000.1nm = subset( lms2000.1nm, 3:1 ) #   reorder from short to long

colorSpec documentation built on June 10, 2025, 5:11 p.m.