Summing a Variable by Group in R: A Comprehensive Guide

Reshaping Data from Long Format to Wide Format without "timevar" Feature

Creating Side-by-Side Plots with ggplot2: A Comparative Guide Using gridExtra, Facets, and cowplot Packages

Understanding the Power of ggplot2 Bar Graphs: Customizing and Ordering for Clear Insights

Replacing NAs with the Latest Non-NA Value Using R's zoo Package

The Great R Package Confusion: Why summarize Doesn't Work with Group By in dplyr

Understanding Grid-Based System Workarounds for Multiple Graphics Generation with ggplot2

Dealing with Interdependent Factors in Linear Models: Strategies for Rank-Deficiency Resolution

Counting Rows Per Group in R Data Frames Using Multiple Methods

Creating a Group Index for Values Connected Directly and Indirectly Using R's igraph Library