Levels And Unique In R

Kevin Feasel

2018-03-14

R

Eric Cai demonstrates the difference between levels() and unique() when dealing with factors in R:

The new data set “iris2” does not have any rows containing “setosa” as a possible value of “Species”, yet the levels() function still shows “setosa” in its output.

According to the user G5W in Stack Overflow, this is a desirable behaviour for the levels() function.  Here is my interpretation of the intent behind the creators of base R: The possible values of a factor are fundamental attributes of that variable, which should not be altered because of changes in the data.

There’s some back-and-forth in the comments; my takeaway is that both are useful functions depending upon what, exactly, you want to learn.

Related Posts

Using wrapr For A Consistent Pipe With ggplot2

John Mount shows how you can use the wrapr pipe to perform data processing and building a ggplot2 visual: Now we can run a single pipeline that combines data processing steps and ggplot plot construction. data.frame(x = 1:20) %.>% mutate(., y = cos(3*x)) %.>% ggplot(., aes(x = x, y = y)) %.>% geom_point() %.>% geom_line() %.>% ggtitle("piped ggplot2") Check […]

Read More

Using R To Hit Azure ML From Power BI

Leila Etaati shows how you can use R to hit an Azure ML endpoint to populate a data set in Power BI: You need to create a model in Azure ML Studio and create a web service for it. The traditional example in Predict a passenger on Titanic ship is going to survived or not? […]

Read More

Categories

March 2018
MTWTFSS
« Feb Apr »
 1234
567891011
12131415161718
19202122232425
262728293031