Handle new default stringsAsFactors setting in R v4.0.0

[ichthya]

Line 67: when reading the data frame we need to add the stringAsFactors = TRUE because of the recent change from the default option TRUE to FALSE in R version 4.0.0. If we do not do that, all the examples in the lesson regarding factors would not be able to be used.

[jsta]

Thanks for catching this! Definitely needs a fix. I wonder if this is a big enough gotcha that we should give it a special "warning" call-out box instead of an inline code comment carpentries/styles#49

[ichthya]

Thanks for catching this! Definitely needs a fix. I wonder if this is a big enough gotcha that we should give it a special "warning" call-out box instead of an inline code comment carpentries/styles#49
I think just adding the stringAsFactor = TRUE might add some confusion to students, especially might give the wrong idea of this being a common practice. But not reading as factors would require some revision in several portions of the lesson. Because this was my first contribution, I suggested the simpler solution, but Im happy to help to modify the lesson in a way that factors come as a secondary point.

[jsta]

See also, datacarpentry/R-ecology-lesson#608

[lachlandeer]

Hi @jsta ,

What's the status with this PR? Can it be integrated, closed or is it part of a bigger project around R 4.0?

[jsta]

I think it can be merged for now. My suggestion is that a future PR be opened more strongly warning about the change to stringsAsFactors. Possibly using the new .caution box style (https://github.com/carpentries/styles/pull/475/files).

[tobyhodges]

Merging this in advance of the lesson infrastructure transition.