Tag: head

R is a case sensitive programming language, which sometimes creates unusual and yet annoying problems for users. A common mistake that I often make when using R is to press the shift button too early when I use the head() function – which results in heaD(). However, this returns an error message (not surprisingly) rather than printing the first six rows of the data. 

> head(mtcars)
                   mpg cyl disp  hp drat    wt  qsec vs am gear carb
Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

> heaD(mtcars)
Error in heaD(mtcars) : could not find function "heaD"

At the beginning, this didn’t bother me since I could easily fix this typo but over time it has become a bit annoying. The faster I typed in R, the more I repeated this mistake. Then I thought creating a heaD() function that does the same job as head() would be the ultimate solution to my problem. Because I would need this “new” function every time I open R, I decided to add it into my .Rprofile file. The .Rprofile file contains R code to be run when R starts up. Typically .Rprofile is located in the user’s home directory. In my computer, I place it under: C:\Users\okanb\OneDrive\Documents

To create a new .Rprofile file, you can simply create a text file using a text editor, add the content to be used when R starts up, and save it as .Rprofile (i.e., no file name and the file extension is .Rprofile).  If you already have this file in your computer, you can simply run usethis::edit_r_profile() to open and edit the file in R. In the file, I added the following line: 

# Create a heaD function
heaD <- function(x) head(x) # or just: heaD <- head

After editing and saving .Rprofile, you need to restart R. From this point on, R will recognize both head() and heaD().

> heaD(mtcars)
                   mpg cyl disp  hp drat    wt  qsec vs am gear carb
Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1