Incorrect Number of Dimensions Error in R (Example)

On this page you’ll learn how to reproduce and debug the error message: “incorrect number of dimensions” in the R programming language.

Example Data

In this tutorial, we’ll use the mtcars data set to illustrate the error message.

data(mtcars)
head(mtcars)

##                    mpg cyl disp  hp drat    wt  qsec vs am gear carb
## Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
## Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
## Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
## Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
## Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
## Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

Reproduce the Error Message

The R code below replicates the error message.

mtcars$mpg[1:3, ]

## Error in mtcars$mpg[1:3, ] : incorrect number of dimensions

Why the Error Message Occurrs

The reason for the occurrence of the error message is that we have specified a comma within the square brackets. This indicates that we are dealing with rows and columns (i.e. two dimensions). However, our data is only one-dimensional (i.e. the column vector mpg).

Debug the Error Message

The R code below fixes the error message.

mtcars$mpg[1:3]

## [1] 21.0 21.0 22.8