Categories / subset
Subsetting the First Row of Each Element in a Variable Using Dplyr
Understanding Factor Levels in R: How to Eliminate Unused Levels with droplevels()
Removing Group IDs Based on Condition in At Least One Group Using R Programming Language.
Logical Subset from Matrix Based on Multiple Columns with No Names
Calculate Seasonal Variations Using lubridate and R: A Step-by-Step Guide
Subsetting Nominal Variables in R: A Comparative Analysis of Data.table, dplyr, and Base R