Create List of Vectors Using Rcpp Package in R (Example)
In the following, we show you how to do create a list of vectors with the Rcpp package in R.
The structure is as follows:
Let’s list some vectors!
Create Example Vectors
First, we need to load the Rcpp package to be able to use C++ code in R.
if (!require('Rcpp', quietly = TRUE)) { install.packages('Rcpp') } library('Rcpp') # Load package 'Rcpp'
We create three example vectors x, y, and z, which we want to combine to a list.
x <- 1:5 # numeric y <- LETTERS[1:10] # string z <- c(TRUE, FALSE, FALSE) # logical
You probably know from your experience with R that we can create unnamed lists and named lists. We show you an example of an unnamed and a named list of vectors x, y, and z in R below. With the example, you can also see that a list can take elements of different forms, types, and sizes.
list(x, y, z) # creates a list without specific names for the list elements # [[1]] # [1] 1 2 3 4 5 # # [[2]] # [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" # # [[3]] # [1] TRUE FALSE FALSE list("a" = x, "b" = y, "c" = z) # creates a list where we specifically name the elements # $a # [1] 1 2 3 4 5 # # $b # [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" # # $c # [1] TRUE FALSE FALSE
Example 1: Unnamed List of Vectors in Rcpp
Like we did in R before, we can create an unnamed list of the three vectors in Rcpp with the function below.
cppFunction(' Rcpp::List f_vec_list( Rcpp::NumericVector x, Rcpp::StringVector y, Rcpp::LogicalVector z) { Rcpp::List res = Rcpp::List::create(x, y, z); return res; } ')
f_vec_list(x, y, z) # [[1]] # [1] 1 2 3 4 5 # # [[2]] # [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" # # [[3]] # [1] TRUE FALSE FALSE
Example 2: Named List of Vectors in Rcpp
Alternatively, we can also create a Rcpp list where we explicitly name the list elements “a”, “b”, and “c”, as shown in the function below.
cppFunction(' Rcpp::List f_vec_named_list( Rcpp::NumericVector x, Rcpp::StringVector y, Rcpp::LogicalVector z) { Rcpp::List res = Rcpp::List::create(Rcpp::Named("a") = x, Rcpp::Named("b") = y, Rcpp::Named("c") = z); return res; } ')
f_vec_named_list(x, y, z) # $a # [1] 1 2 3 4 5 # # $b # [1] "A" "B" "C" "D" "E" "F" "G" "H" "I" "J" # # $c # [1] TRUE FALSE FALSE
Video & Further Resources
For more information on Rcpp, we recommend you to take a look at the official Rcpp homepage here. Furthermore, on the CRAN page of Rcpp, which you can find here, you can find some useful additional references.
On https://statisticsglobe.com/, we have many more blog posts which you might want to look at:
- Create Data Frame & Matrix Using Rcpp Package in R (4 Examples)
- Loop Over Rows & Columns of Rcpp Matrix in R (2 Examples)
- Introduction to the Rcpp Package in R (Examples)
- Learn R Programming (Tutorial & Examples)
We showed you how to create a list of vectors in Rcpp. If you have questions or comments, get in contact with us using the comment section below.
This page was created in collaboration with Anna-Lena Wölwer. Have a look at Anna-Lena’s author page to get further information about her academic background and the other articles she has written for Statistics Globe.
I’m Joachim Schork. On this website, I provide statistics tutorials as well as code in Python and R programming.
