Identify cases where stringsAsFactors should be supplied explicitly
Source:R/strings_as_factors_linter.R
strings_as_factors_linter.Rd
Designed for code bases written for versions of R before 4.0 seeking to upgrade to R >= 4.0, where
one of the biggest pain points will surely be the flipping of the
default value of stringsAsFactors
from TRUE
to FALSE
.
Details
It's not always possible to tell statically whether the change will break
existing code because R is dynamically typed -- e.g. in data.frame(x)
if x
is a string, this code will be affected, but if x
is a number,
this code will be unaffected. However, in data.frame(x = 'a')
, the
output will unambiguously be affected. We can instead supply
stringsAsFactors = TRUE
, which will make this code backwards-compatible.
See https://developer.r-project.org/Blog/public/2020/02/16/stringsasfactors/.
See also
linters for a complete list of linters available in lintr.