R Using apply() Function Only for Certain Columns of a Data Frame (Example Code)
This tutorial explains how to use the apply function only for some selected columns in the R programming language.
Creation of Example Data
data(iris) # Iris data set head(iris) # 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) # Iris data set head(iris) # 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
Example: Using apply() Function for Specific Variables of Data Frame
iris_new <- data.frame(apply(iris[ , 1:2], 2, cumsum), # Apply cumsum function to certain columns iris[ , 3:ncol(iris)]) head(iris_new) # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 2 10.0 6.5 1.4 0.2 setosa # 3 14.7 9.7 1.3 0.2 setosa # 4 19.3 12.8 1.5 0.2 setosa # 5 24.3 16.4 1.4 0.2 setosa # 6 29.7 20.3 1.7 0.4 setosa |
iris_new <- data.frame(apply(iris[ , 1:2], 2, cumsum), # Apply cumsum function to certain columns iris[ , 3:ncol(iris)]) head(iris_new) # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 2 10.0 6.5 1.4 0.2 setosa # 3 14.7 9.7 1.3 0.2 setosa # 4 19.3 12.8 1.5 0.2 setosa # 5 24.3 16.4 1.4 0.2 setosa # 6 29.7 20.3 1.7 0.4 setosa