(TypeError:) Cannot read properties of null (reading: 'substr')

[skeptikantin]

Hi there,
Does anyone know what this notification means? I cannot use autocompletion, no suggestions are showing. I can however type the column name (which is a bit tedious remembering...). It was working fine a few hours ago and stopped from one minute to the next, without any obvious action on my part. When googling, I found other TypeErrors, but none reported the same issues. Edit: I restarted RStudio and computer, it is working fine in R itself, and the message shows on several RStudio projects.
Any pointers much appreciated.

[prubin]

I can't reproduce that error message here, but I can say that your sample code looks suspicious. Apparently errors begins life as a matrix or data frame, but when you assign the calculation to errors$ratio you coerce it into a list. If you are trying to add a column to the errors matrix, what you want is errors <- cbind(errors, 1 - (errors[,3]/rowSums(errors))). You can then assign the name "ratio" to the extra column if so desired.

[skeptikantin]

Hi there, thanks for taking the time to respond.

The above code may not have been the most illustrative example, it was the code I just happened to have used to test last before posting. You are correct, this particular object's life does start as some form of a matrix (as.dataframe.matrix()), but I use that function on a daily basis, and I could have taken a screenshot of any other project where the TypeError occurred that did not involve as.dataframe.matrix().

The weird thing is that the TypeError popped up out of the blue in a project I had been working on all day, and where I could access df columns normally just a minute before. For those projects it has since disappeared, i.e., the above example is actually the only case where I can now reproduce the TypeError. What is weird tho is that it seems to be an ordinary dataframe, and I can access the column names with $-tabcompletion for that object in R, and R/RStudio both print the column if I type the column name out - it's just that tab/autocompletion in RStudio seems compromised of some sort. It's very odd and unexpected behavior I have not seen before, and I use as.dataframe.matrix() a lot across many projects.

tl;dr. I'm happy to accept it is/was some random fluke caused by some background process or own unintentional action or whatnot, and I was curious why it occurred and wasn't resolved after a laptop and RStudio / session restart. Thanks again.

Screenshot of R.

[skeptikantin]

I spoke too soon, it's back - but it happens intermittently. I'm sure it's got to do with some background process, I cannot make any sense of it yet.