Functions for changing levels

[jariji]

R's Forcats has a lot of nice functions for changing levels. I find myself wanting these quite often.

https://forcats.tidyverse.org/reference/index.html

[nalimilan]

See previous discussion at #368. Could you give more details about what features you would need in particular?

[jariji]

For example I would like:

• fct_infreq
• fct_explicit_na
• fct_drop