Description Usage Arguments Details Value Author(s) Examples
If wavelength
is numeric, each of its elements is converted to the respective index.
Values outside the range of x@wavelength
become NA
.
1 2 3 |
x |
a |
wavelength |
the wavelengths to be converted into column indices, either numeric or a formula, see details. |
i |
the column indices into the spectra matrix for which the wavelength is to be computed |
If the range is given as a formula (i.e. start ~ end
, a sequence
index corresponding to start : index corresponding to end
is returned. If the wavelengths are not ordered, that may lead to chaos. In this case, call
orderwl
first.
Two special variables can be used: min
and max
, corresponding to the lowest and
highest wavelength of x
, respectively.
start and end may be complex numbers. The resulting index for a complex x is then
index (Re (x)) + Im (x)
A numeric containing the resulting indices for wl2i
i2wl
returns a numeric with the wavelengths
C. Beleites
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 | flu
wl2i (flu, 405 : 407)
wl2i (flu, 405 ~ 407)
## beginning of the spectrum to 407 nm
wl2i (flu, min ~ 407)
## 2 data points from the beginning of the spectrum to 407 nm
wl2i (flu, min + 2i ~ 407)
## the first 3 data points
wl2i (flu, min ~ min + 2i)
## from 490 nm to end of the spectrum
wl2i (flu, 490 ~ max)
## the last 8 data points
wl2i (flu, max - 7i ~ max)
## get 450 nm +- 3 data points
wl2i (flu, 450 - 3i ~ 450 + 3i)
wl2i (flu, 300 : 400) ## all NA:
wl2i (flu, 600 ~ 700) ## NULL: completely outside flu's wavelength range
i2wl (chondro, 17:20)
|
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