R Subset of Data Frame Error – Undefined Columns Selected (Example Code)
In this tutorial, I’ll explain how to handle the error message “Undefined Columns Selected” in R programming.
Introducing Example Data
data(iris) # Load data 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) # Load data 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: Replicating & Fixing Error: Undefined Columns Selected
iris[iris$Sepal.Length > 5] # Replicate error (no comma used) # Error in `[.data.frame`(iris, iris$Sepal.Length > 5) : # undefined columns selected |
iris[iris$Sepal.Length > 5] # Replicate error (no comma used) # Error in `[.data.frame`(iris, iris$Sepal.Length > 5) : # undefined columns selected
We have to use a comma within the square brackets:
iris[iris$Sepal.Length > 5, ] # Fixing error by specifying a comma # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 6 5.4 3.9 1.7 0.4 setosa # 11 5.4 3.7 1.5 0.2 setosa # 15 5.8 4.0 1.2 0.2 setosa # 16 5.7 4.4 1.5 0.4 setosa # 17 5.4 3.9 1.3 0.4 setosa |
iris[iris$Sepal.Length > 5, ] # Fixing error by specifying a comma # Sepal.Length Sepal.Width Petal.Length Petal.Width Species # 1 5.1 3.5 1.4 0.2 setosa # 6 5.4 3.9 1.7 0.4 setosa # 11 5.4 3.7 1.5 0.2 setosa # 15 5.8 4.0 1.2 0.2 setosa # 16 5.7 4.4 1.5 0.4 setosa # 17 5.4 3.9 1.3 0.4 setosa