sample: Random Samples and Permutations Take a sample of the...

In hyperSpec: Work with Hyperspectral Data, i.e. Spectra + Meta Information (Spatial, Time, Concentration, ...)

Description

Random Samples and Permutations Take a sample of the specified size from the elements of x with or without replacement.

isample returns an vector of indices, sample returns the corresponding hyperSpec object.

Usage

## S4 method for signature 'hyperSpec'
sample(x, size = nrow(x), replace = FALSE,
  prob = NULL)

isample(x, size = nrow(x), replace = FALSE, prob = NULL)

## S4 method for signature 'data.frame'
sample(x, size = nrow(x), replace = FALSE,
  prob = NULL, drop = FALSE)

## S4 method for signature 'matrix'
sample(x, size = nrow(x), replace = FALSE, prob = NULL,
  drop = FALSE)

Arguments

x	The hyperSpec object, data.frame or matrix to sample fromto sample from
size	positive integer giving the number of spectra (rows) to choose.
replace	Should sampling be with replacement?
prob	A vector of probability weights for obtaining the elements of the vector being sampled.
drop	see drop: by default, do not drop dimensions of the result

Value

a hyperSpec object, data.frame or matrix with size rows for sample, and an integer vector for isample that is suitable for indexing (into the spectra) of x.

vector with indices suitable for row-indexing x

Author(s)

C. Beleites

See Also

sample

Examples

sample (flu, 3)

plot (flu, col = "darkgray")
plot (sample (flu, 3), col = "red", add = TRUE)

plot (flu, col = "darkgray")
plot (sample (flu, 3, replace = TRUE), col = "#0000FF80", add = TRUE,
      lines.args = list (lwd = 2));
isample (flu, 3)
isample (flu, 3, replace = TRUE)
isample (flu, 8, replace = TRUE)
sample (cars, 2)
sample (matrix (1:24, 6), 2)

Example output

Loading required package: lattice
Loading required package: grid
Loading required package: ggplot2
Package hyperSpec, version 0.99-20180627

To get started, try
   vignette ("hyperspec")
   package?hyperSpec 
   vignette (package = "hyperSpec")

If you use this package please cite it appropriately.
   citation("hyperSpec")
will give you the correct reference.

The project homepage is http://hyperspec.r-forge.r-project.org


hyperSpec object
   3 spectra
   3 data columns
   181 data points / spectrum
wavelength: lambda/nm [numeric] 405.0 405.5 ... 495 
data:  (3 rows x 3 columns)
   1. spc: I[fl]/"a.u." [matrix181] 66.80133 93.14433 ... 195.8673 
   2. filename: filename [character] rawdata/flu2.txt rawdata/flu3.txt rawdata/flu4.txt 
   3. c: c / (mg / l) [numeric] 0.10 0.15 0.20 
[1] 6 1 4
[1] 3 5 4
[1] 3 5 3 3 2 1 3 5
   speed dist
16    13   26
8     10   26
     [,1] [,2] [,3] [,4]
[1,]    4   10   16   22
[2,]    6   12   18   24

hyperSpec documentation built on May 2, 2019, 5:45 p.m.