Remove most references to factors, closes #1151

Author: krlmlr

README.Rmd

@@ -64,7 +64,7 @@ You can also create a new tibble from column vectors with `tibble()`:
 tibble(x = 1:5, y = 1, z = x^2 + y)
 ```
 
-`tibble()` does much less than `data.frame()`: it never changes the type of the inputs (e.g. it never converts strings to factors!), it never changes the names of variables, it only recycles inputs of length 1, and it never creates `row.names()`. You can read more about these features in `vignette("tibble")`.
+`tibble()` does much less than `data.frame()`: it never changes the type of the inputs (e.g. it keeps list columns unchanged, and never converts strings to factors!), it never changes the names of variables, it only recycles inputs of length 1, and it never creates `row.names()`. You can read more about these features in `vignette("tibble")`.
 
 You can define a tibble row-by-row with `tribble()`:
 
@@ -78,7 +78,7 @@ tribble(
 
 ## Related work
 
-The tibble print method draws inspiration from [data.table](https://rdatatable.gitlab.io/data.table), and [frame](https://github.com/patperry/r-frame). Like `data.table::data.table()`, `tibble()` doesn't coerce strings to factors by default, doesn't change column names, and doesn't use rownames.
+The tibble print method draws inspiration from [data.table](https://rdatatable.gitlab.io/data.table), and [frame](https://github.com/patperry/r-frame). Like `data.table::data.table()`, `tibble()` doesn't change column names and doesn't use rownames.
 
 ---
 ## Code of Conduct

README.md

@@ -65,7 +65,7 @@ You can also create a new tibble from column vectors with [`tibble()`](https://t
 <span><span class='c'>#&gt; <span style='color: #555555;'>4</span>     4     1    17</span></span>
 <span><span class='c'>#&gt; <span style='color: #555555;'>5</span>     5     1    26</span></span></pre>
 
-[`tibble()`](https://tibble.tidyverse.org/reference/tibble.html) does much less than [`data.frame()`](https://rdrr.io/r/base/data.frame.html): it never changes the type of the inputs (e.g. it never converts strings to factors!), it never changes the names of variables, it only recycles inputs of length 1, and it never creates [`row.names()`](https://rdrr.io/r/base/row.names.html). You can read more about these features in [`vignette("tibble")`](https://tibble.tidyverse.org/articles/tibble.html).
+[`tibble()`](https://tibble.tidyverse.org/reference/tibble.html) does much less than [`data.frame()`](https://rdrr.io/r/base/data.frame.html): it never changes the type of the inputs (e.g. it keeps list columns unchanged, and never converts strings to factors!), it never changes the names of variables, it only recycles inputs of length 1, and it never creates [`row.names()`](https://rdrr.io/r/base/row.names.html). You can read more about these features in `vignette("tibble")`.
 
 You can define a tibble row-by-row with [`tribble()`](https://tibble.tidyverse.org/reference/tribble.html):
 
@@ -83,7 +83,7 @@ You can define a tibble row-by-row with [`tribble()`](https://tibble.tidyverse.o
 
 ## Related work
 
-The tibble print method draws inspiration from [data.table](https://rdatatable.gitlab.io/data.table), and [frame](https://github.com/patperry/r-frame). Like [`data.table::data.table()`](https://Rdatatable.gitlab.io/data.table/reference/data.table.html), [`tibble()`](https://tibble.tidyverse.org/reference/tibble.html) doesn’t coerce strings to factors by default, doesn’t change column names, and doesn’t use rownames.
+The tibble print method draws inspiration from [data.table](https://rdatatable.gitlab.io/data.table), and [frame](https://github.com/patperry/r-frame). Like [`data.table::data.table()`](https://Rdatatable.gitlab.io/data.table/reference/data.table.html), [`tibble()`](https://tibble.tidyverse.org/reference/tibble.html) doesn’t change column names and doesn’t use rownames.
 
 ------------------------------------------------------------------------
 

tests/testthat/_snaps/vignette-tibble/tibble.md

@@ -10,8 +10,7 @@ vignette: >
 
 
 Tibbles are a modern take on data frames.
-They keep the features that have stood the test of time, and drop the features that used to be convenient but are now frustrating (i.e.
-converting character vectors to factors).
+They keep the features that have stood the test of time, and drop the features that used to be convenient but are now frustrating.
 
 
 ```r

vignettes/tibble.Rmd

@@ -17,8 +17,7 @@ knitr::opts_chunk$set(
 ```
 
 Tibbles are a modern take on data frames.
-They keep the features that have stood the test of time, and drop the features that used to be convenient but are now frustrating (i.e.
-converting character vectors to factors).
+They keep the features that have stood the test of time, and drop the features that used to be convenient but are now frustrating.
 
 ```{r}
 library(tibble)