Selecting and Filtering on the Same Variables in dplyr

Understanding the Issue with Subsetting R Data Frame Results in Mysterious NA Rows

Merging Rows Based on Conditional Criteria in DataFrames Using SQL

Subset Data for a Specific Column with ddply: A Deep Dive in R

Subsetting Panel Data in R: A Comparative Analysis of Base R and data.table Package

Subsetting Survey Design Objects Dynamically in R