Sometimes it’s useful to write down the various classes of vectors inside your data.frame objects for documentation and other people to use it.

I’ve searched for a quick way to find out all the classes of vectors inside a data.frame.

Since I’ve found no reference for such a function/process I made one up.

I’d like to hear what people have to say about the following use of the “class” function on data.frames

a simple call :

> library(rpart) # comes with R
> data(kyphosis) # comes with rpart
> class(kyphosis)
"data.frame"
trying to use the “apply” function to know what classes are the columns in the data.frame yeilds the following unwanted result :

> apply(kyphosis,2,class)
Kyphosis Age Number Start
"character" "character" "character" "character"
For some reason the apply function returns “character” on all vectors regardless of their true content (any ideas why?).

Anyhow, after some thought I’ve come up with the following function :

> allClass <- function(x) {unlist(lapply(unclass(x),class))}
> allClass(kyphosis)
Kyphosis Age Number Start
"factor" "integer" "integer" "integer"
Compact, fast and quite useful. Of course the control flow needs more work to fit other classes and recognize when x is not a data.frame.

Comments are welcome.

Related

To

leave a comment for the author, please follow the link and comment on their blog:

My contRibution » R .

R-bloggers.com offers

daily e-mail updates about

R news and

tutorials on topics such as:

Data science ,

Big Data, R jobs , visualization (

ggplot2 ,

Boxplots ,

maps ,

animation ), programming (

RStudio ,

Sweave ,

LaTeX ,

SQL ,

Eclipse ,

git ,

hadoop ,

Web Scraping ) statistics (

regression ,

PCA ,

time series ,

trading ) and more...

If you got this far, why not

subscribe for updates from the site? Choose your flavor:

e-mail ,

twitter ,

RSS , or

facebook ...