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Discover how to effectively merge multiple data frames in R while avoiding duplicated column names by using data frame names as suffixes in your joins.
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How to Use dataframe Names as Suffixes When Joining Multiple Data Frames in R

Merging data frames in R, especially when you have duplicated column names, can often lead to confusion. If you've ever used dplyr::left_join combined with purrr::reduce to merge several data frames and found that the default suffixes aren't enough to identify the source of each column, you’re not alone. The standard behavior of dplyr::left_join adds a suffix for duplicated column names, but without knowing which data frame each variable belongs to, your task can become cumbersome.

The Problem

To illustrate, let's look at a situation where we have several data frames:

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When we perform a left join:

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You'll end up with a data frame looking like this:

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As evident, the columns var from each data frame now have suffixes .x and .y, which doesn't tell you which data frame the values originated from. What if you wanted to use the original data frame names as suffixes (e.g., var.a, var.b, var.c)?

Solution: Using Data Frame Names as Suffixes

There are two primary approaches to solve this problem, allowing you to retain the context of where each variable comes from when merging data frames.

Approach 1: Rename Before Joining

Rename Non-Join Columns: Prior to executing the join, we can rename the columns in each data frame to include the name of the data frame.

Here's how to do it:

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This final output will give you a well-organized tibble:

[[See Video to Reveal this Text or Code Snippet]]

Approach 2: Process the List Before Joining

Using a Function to Add Suffixes: Alternatively, you can avoid the complications of regular expressions by defining a function that handles these renames prior to the joins:

[[See Video to Reveal this Text or Code Snippet]]

This method also provides a clean output without the need for complex post-processing.

Conclusion

Using data frame names as suffixes when merging multiple data frames not only enhances the clarity of your data but also maintains the context of where each value originates from. Depending on your needs, you can choose either to rename the columns before joining or to write a function that automatically handles the suffix addition. These steps will make your data analysis in R smoother and more efficient. Happy coding!