apply_by_groups: Apply by groups
In specmine: Metabolomics and Spectral Data Analysis and Mining

Description Usage Arguments Value Examples

Apply a function to samples from a metadata's variable.

1 2	apply_by_groups(dataset, metadata.var, fn.to.apply = "mean", variables = NULL, variable.bounds = NULL)

`dataset`	list representing the dataset from a metabolomics experiment.
`metadata.var`	name of the metadata's variable.
`fn.to.apply`	function to apply (e.g. mean, max, min).
`variables`	allows to define which variables to calculate the stats (if numbers, indexes are assumed).
`variable.bounds`	allow to define an interval of variables (if numeric).

Returns a vector with the variables and the value of the applied function on the metadata's groups.

     ## Example of applying a function to groups
	 library(specmine.datasets)
     data(cachexia)
     apply.groups.result = apply_by_groups(cachexia, "Muscle.loss", mean)