R How to Append Several Variables to data.table (Example Code)
This tutorial explains how to append several new data.table variables in the R programming language.
Preparing the Example
install.packages("data.table") # Install & load data.table package library("data.table") |
install.packages("data.table") # Install & load data.table package library("data.table")
data(iris) # Load iris data set iris_dt <- as.data.table(iris) # Convert iris to data.table head(iris_dt) # Show head of data.table in RStudio # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1: 5.1 3.5 1.4 0.2 setosa # 2: 4.9 3.0 1.4 0.2 setosa # 3: 4.7 3.2 1.3 0.2 setosa # 4: 4.6 3.1 1.5 0.2 setosa # 5: 5.0 3.6 1.4 0.2 setosa # 6: 5.4 3.9 1.7 0.4 setosa |
data(iris) # Load iris data set iris_dt <- as.data.table(iris) # Convert iris to data.table head(iris_dt) # Show head of data.table in RStudio # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1: 5.1 3.5 1.4 0.2 setosa # 2: 4.9 3.0 1.4 0.2 setosa # 3: 4.7 3.2 1.3 0.2 setosa # 4: 4.6 3.1 1.5 0.2 setosa # 5: 5.0 3.6 1.4 0.2 setosa # 6: 5.4 3.9 1.7 0.4 setosa
new1 <- 1:nrow(iris_dt) # Create two vector objects in R head(new1) # [1] 1 2 3 4 5 6 |
new1 <- 1:nrow(iris_dt) # Create two vector objects in R head(new1) # [1] 1 2 3 4 5 6
new2 <- nrow(iris_dt):1 head(new2) # [1] 150 149 148 147 146 145 |
new2 <- nrow(iris_dt):1 head(new2) # [1] 150 149 148 147 146 145
Example: Appending Multiple Vectors as New Columns to data.table
iris_dt[ , `:=` (new1 = new1, new2 = new2)] # Adding new variables to data.table head(iris_dt) # Show new data.table in RStudio # Sepal.Length Sepal.Width Petal.Length Petal.Width Species new1 new2 # 1: 5.1 3.5 1.4 0.2 setosa 1 150 # 2: 4.9 3.0 1.4 0.2 setosa 2 149 # 3: 4.7 3.2 1.3 0.2 setosa 3 148 # 4: 4.6 3.1 1.5 0.2 setosa 4 147 # 5: 5.0 3.6 1.4 0.2 setosa 5 146 # 6: 5.4 3.9 1.7 0.4 setosa 6 145 |
iris_dt[ , `:=` (new1 = new1, new2 = new2)] # Adding new variables to data.table head(iris_dt) # Show new data.table in RStudio # Sepal.Length Sepal.Width Petal.Length Petal.Width Species new1 new2 # 1: 5.1 3.5 1.4 0.2 setosa 1 150 # 2: 4.9 3.0 1.4 0.2 setosa 2 149 # 3: 4.7 3.2 1.3 0.2 setosa 3 148 # 4: 4.6 3.1 1.5 0.2 setosa 4 147 # 5: 5.0 3.6 1.4 0.2 setosa 5 146 # 6: 5.4 3.9 1.7 0.4 setosa 6 145
Further Resources & Related Tutorials
You may find some additional R tutorials on topics such as variables and loops below: