Gets the index of a defined wavenumber value for a spectrum

ir_get_wavenumberindex gets for a defined wavenumber value or set of wavenumber values the corresponding indices (row number) in an object of class ir that has been flattened with ir_flatten(). If the specified wavenumber values do not match exactly the wavenumber values in the ir object, the indices for the next wavenumber values will be returned, along with a warning.

Usage

ir_get_wavenumberindex(x, wavenumber, warn = TRUE)

Arguments

x

A data.frame with a column x representing the x units of a spectrum or several spectra (e.g. in the form of an object of class ir_flat).

wavenumber

A numeric vector with wavenumber values for which to get indices.

warn

logical value indicating if warnings should be displayed (TRUE) or not (FALSE).

Value

An integer vector with the same length as wavenumber with the row indices of x corresponding to the wavenumber values in wavenumber.

Examples

x_index_1090 <-
   ir::ir_sample_data |>
   ir::ir_flatten() |>
   ir::ir_get_wavenumberindex(wavenumber = 1090)