Getting Distinct Rows In R

Kevin Feasel



Rob J. Hyndman shows four different techniques (one “classic” and three tidyverse) for getting a distinct subset of a data set in R:

So that looks much better — clean, short, and easy to understand. But is it fast? Rather than grabbing the first lines of each group, it has to go searching for duplicates. But avoiding grouping and ungrouping must save some time.

So I ran some microbenchmark timings:

Click through for techniques and timings.  I’m not surprised that the “classic” method won out in terms of time, but for explanatory value, I’d definitely prefer trying to explain the tidyverse distinct version.  H/T R-Bloggers

Related Posts

R 3.5.0 Released

Tal Galili announces that R 3.5.0 is now available: By default the (arbitrary) signs of the loadings from princomp() are chosen so the first element is non-negative. If –default-packages is not used, then Rscript now checks the environment variable R_SCRIPT_DEFAULT_PACKAGES. If this is set, then it takes precedence over R_DEFAULT_PACKAGES. If default packages are not specified on the command line or by one […]

Read More

Issues Starting ML Services

Jen Stirrup has a quick rundown of some reasons why Machine Learning Services might give you an error when you try to start it up: Msg 39023, Level 16, State 1, Procedure sp_execute_external_script, Line 1 [Batch Start Line 3] ‘sp_execute_external_script’ is disabled on this instance of SQL Server. Use sp_configure ‘external scripts enabled’ to enable […]

Read More


September 2017
« Aug Oct »