Retrieves the values in the group_DF attribute from an omicsData object.
get_group_DF(omicsData)An object of class pepData, proData, metabData, lipidData, or nmrData.
A data.frame with columns for sample ID and group. If two main effects are provided the original main effect levels for each sample are returned as the third and fourth columns of the data frame. Additionally, the covariates provided will be listed as attributes of this data frame.