List Error in R – attempt to select less than one element in get1index real

In this tutorial you’ll learn how to reproduce and handle the error message “attempt to select less than one element in get1index real” in R programming.

The tutorial will contain two examples for the handling of the error “attempt to select less than one element in get1index real”. More precisely, the article looks as follows:

So without further ado, let’s take a look at some R codes in action:

Example Data

As a first step, we’ll have to construct some data that we can use in the examples later on:

my_list <- list(1:5,        # Create example list
                "XX",
                letters[7:4])
my_list                     # Print example list
# [[1]]
# [1] 1 2 3 4 5
# 
# [[2]]
# [1] "XX"
# 
# [[3]]
# [1] "g" "f" "e" "d"
#

Have a look at the previous output of the RStudio console. It shows that our example data is a list with three different list elements.

Example 1: Reproduce the Error – attempt to select less than one element in get1index real

The following R code explains how to replicate the error “attempt to select less than one element in get1index real” in the R programming language.

Let’s assume that we want to extract a particular element from our list. Then, we might try to use the following R code:

my_list[[0]]                # Try to select 0-element
# Error in my_list[[0]] : 
#   attempt to select less than one element in get1index <real>

As you can see, the RStudio console has returned the error “attempt to select less than one element in get1index real” after executing the previous syntax.

The reason for this is that we have tried to select the 0th element of our list, i.e. a list element that does not exist.

In our example this mistake might be obvious. However, in more complex R codes such as for-loops or user defined functions this mistake occurs quite often.

So how can we solve this problem?

Example 2: Fix the Error – attempt to select less than one element in get1index real

The following R code demonstrates how to debug the error message “attempt to select less than one element in get1index real”.

In our example, we can simply use an index greater than 0. For example, the following R code returns the first list element of our example list:

my_list[[1]]                # Properly select list element
# [1] 1 2 3 4 5

However, in loops or manually defined functions you may run your code line by line to see at which point the running index is equal to zero and at which point the error message pops up.

Video & Further Resources

Do you need more info on the content of this article? Then you might have a look at the following video which I have published on my YouTube channel. In the video, I illustrate the contents of the present tutorial.

The YouTube video will be added soon.

Furthermore, you may have a look at the related articles of www.statisticsglobe.com:

• Select First Element of Nested List in R
• Error in read.table : more columns than column names
• predict Error in eval(predvars, data, env) : numeric ‘envir’ arg not of length one
• Dealing with Warning & Error Messages in R (Overview)
• The R Programming Language

In summary: In this R programming post you have learned how to deal with the error “attempt to select less than one element in get1index real”. If you have further questions and/or comments, please let me know in the comments section. Furthermore, don’t forget to subscribe to my email newsletter to get updates on the newest tutorials.