seq: Sequence generation along spectra or wavelengths This...
In hyperSpec: Work with Hyperspectral Data, i.e. Spectra + Meta Information (Spatial, Time, Concentration, ...)

Description Usage Arguments Details Value Author(s) See Also Examples

Note that wl2i generates sequences of indices along the wavelength axis.

1 2	## S3 method for class 'hyperSpec' seq(x, from = 1, to = nrow(x), ..., index = FALSE)

`x`	the hyperSpec object
`from, to`	arguments handed to `seq.int`
`...`	arguments for `seq`, namely `by`, `length.out`
`index`	should a vector with indices be returned rather than a hyperSpec object?

seq had to be implemented as S3 method as the generic has only ... arguments (on which no dispatch with differing types is possible).

seq_along is not generic, but returns a sequence of the length of the object. As hyperSpec provides a Method length, it can be used. The result is a sequence of indices for the spectra.

a numeric or hyperSpec object, depending on index.

C. Beleites

wl2i to construct sequences of wavelength indices.

seq

seq (flu, index = TRUE)
seq_along (flu)
seq (flu, length.out = 3, index = TRUE) # return value is numeric, not integer! 
seq (flu, by = 2, index = TRUE) 		    # return value is numeric, not integer! 

plot (flu, col = "darkgray") 
plot (seq (flu, by = 2), add = TRUE, col= "red")
plot (seq (flu, length.out = 2), add = TRUE, col= "blue")