Error message when null data frame?

[rdstern]

This problem came to mind with @Patowhiz mentioning the null data book in trying to resolve @Wycklife error #7489. I give the route to my set of error messages and I am not sure we need to do anything about it. a) I had a data frame with a factor. I made filter from factor and used 6 levels, so I made 6 filters. b) Then I discovered a mistake in the name of one level of the factor. I corrected it. c) Then I filtered on the old name. The filter works fine, but there is then no data in the filtered set. d) There are many other ways of getting an empty filtered set, some factor levels may have zeros, or we may select a condition, e.g. year ==2023 that has no rows. e) Now I use a dialogue. I started with the Describe > One Variable > Summarise and that works fine. But One Variable Graph gives an error. I suspect many graphs will give an error. Not surprising - it is pretty silly to use no data.

I just wonder if this is a situation we could trap better - perhaps more generally - and give a sensible message?

[Patowhiz]

@rdstern going by your explanation, I think you meant Error message when data frame has no rows? as the issue title.

[Patowhiz]

This can be implemented at the R level. And obviously the message can be displayed at the VB.Net level.