Collapsing or Concatenating Text in R

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When working with data frames in R, you may often encounter scenarios where you need to collapse or concatenate text values based on groups within your dataset. This could involve combining text from multiple rows into a single row per group, which can be useful for summarizing data or preparing it for further analysis. In this post, we’ll explore how to achieve this task using different methods in R—specifically using base R, the dplyr package, and the data.table package.

This is the R equivalent of T-SQL’s STRING_AGG() function, or the STUFF() + FOR XML PATH approach if you’re still on an older version of SQL Server.