This function efficiently averages the samples spectra in a large
dataset. It provides flexibility by computing either the overall
mean across all spectra or group-wise means based on the values of a
specified grouping column.
Usage
average(x, .group_by = NULL)
Arguments
- x
A data frame or tibble.
- .group_by
The column to group the data by (optional), given either
unquoted or as a string. If not provided, the average of the overall data
will be computed.
Value
If .group_by = NULL, a one-row tibble containing the mean of each column.
If .group_by is provided, a tibble with one row per group: the first
column holds the group labels and the remaining columns hold the group means.
Details
The function leverages the power of Rcpp to perform the mean calculations
in C++. The underlying C++ implementation has a time complexity of
O(n x m), where n is the number of rows and m is
the number of columns in the data. Missing values are ignored in the
computation of each mean.
Author
Christian L. Goueguel
Examples
data(forageLIBS)
# one mean spectrum per sample: three samples were measured twice
means <- average(forageLIBS[-c(1, 3:14)], Sample)
dim(means)
#> [1] 365 7153
