R Error: Replacement has X Rows, Data has Y (2 Examples)

This tutorial explains how to handle the error message “replacement has X rows, data has Y” in the R programming language.

The tutorial consists of this information:

Let’s take a look at some R codes in action:

Constructing Example Data

The following data will be used as basement for this R programming language tutorial:

data <- data.frame(x1 = c(1, 1, 2, 3, 4),       # Create example data
                   x2 = "x")
data                                            # Print example data
#   x1 x2
# 1  1  x
# 2  1  x
# 3  2  x
# 4  3  x
# 5  4  x

As you can see based on the previous output of the RStudio console, the example data has five rows and two columns.

Example 1: Reproduce the Error: Replacement has X Rows, Data has Y

The following R syntax illustrates how to replicate the error message “replacement has X rows, data has Y”.

Let’s assume that we want to create a new data frame variable based on the values of the variable x1. Then, we might try to use the which function as shown in the following R code:

data$x1_range[which(data$x1 <= 2)] <- "<= 2"    # Try to create new variable
# Error in `$<-.data.frame`(`*tmp*`, x1_range, value = c("<= 2", "<= 2",  : 
#   replacement has 3 rows, data has 5

Unfortunately, the previous R syntax resulted in the error “replacement has X rows, data has Y”. The reason for that is that we didn’t create the new variable first, before we assigned values to it.

Let me explain…

Example 2: Fix the Error: Replacement has X Rows, Data has Y

This section shows how to solve the problems with the error message “replacement has X rows, data has Y”.

In order to avoid this error, we first have to append a new column to our data frame that contains only NA values:

data$x1_range <- NA                             # Initialize empty variable first

Now, we can apply exactly the same R code as we did in the previous example:

data$x1_range[which(data$x1 <= 2)] <- "<= 2"    # Fill in values

data                                            # Print updated data frame
#   x1 x2 x1_range
# 1  1  x     <= 2
# 2  1  x     <= 2
# 3  2  x     <= 2
# 4  3  x     <NA>
# 5  4  x     <NA>

This time it worked! We have created a new column with conditional values.

Video, Further Resources & Summary

I have recently released a video tutorial on my YouTube channel, which illustrates the R codes of the present tutorial. You can find the video below:

The YouTube video will be added soon.

Furthermore, you could read the related articles of this homepage. I have released several articles already:

• Warnings & Errors in R (List with Examples)
• Introduction to R

At this point you should know how to deal with the error message “replacement has X rows, data has Y” in the R programming language. If you have any further questions, let me know in the comments section.