Running examples in ‘dplyr-Ex.R’ failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: nest_by
> ### Title: Nest by one or more variables
> ### Aliases: nest_by
> ### Keywords: internal
> 
> ### ** Examples
> 
> # After nesting, you get one row per group
> iris %>% nest_by(Species)
# A tibble: 3 × 2
# Rowwise:  Species
  Species                  data
  <fct>      <list<tibble[,4]>>
1 setosa               [50 × 4]
2 versicolor           [50 × 4]
3 virginica            [50 × 4]
> starwars %>% nest_by(species)
# A tibble: 38 × 2
# Rowwise:  species
   species                  data
   <chr>     <list<tibble[,13]>>
 1 Aleena               [1 × 13]
 2 Besalisk             [1 × 13]
 3 Cerean               [1 × 13]
 4 Chagrian             [1 × 13]
 5 Clawdite             [1 × 13]
 6 Droid                [6 × 13]
 7 Dug                  [1 × 13]
 8 Ewok                 [1 × 13]
 9 Geonosian            [1 × 13]
10 Gungan               [3 × 13]
# ℹ 28 more rows
> 
> # The output is grouped by row, which makes modelling particularly easy
> models <- mtcars %>%
+   nest_by(cyl) %>%
+   mutate(model = list(lm(mpg ~ wt, data = data)))
> models
# A tibble: 3 × 3
# Rowwise:  cyl
    cyl                data model 
  <dbl> <list<tibble[,10]>> <list>
1     4           [11 × 10] <lm>  
2     6            [7 × 10] <lm>  
3     8           [14 × 10] <lm>  
> 
> models %>% summarise(rsq = summary(model)$r.squared)
`summarise()` has grouped output by 'cyl'. You can override using the `.groups`
argument.
# A tibble: 3 × 2
# Groups:   cyl [3]
    cyl   rsq
  <dbl> <dbl>
1     4 0.509
2     6 0.465
3     8 0.423
> ## Don't show: 
> if (requireNamespace("broom", quietly = TRUE)) (if (getRversion() >= "3.4") withAutoprint else force)({ # examplesIf
+ ## End(Don't show)
+ 
+ # This is particularly elegant with the broom functions
+ models %>% summarise(broom::glance(model))
+ models %>% reframe(broom::tidy(model))
+ ## Don't show: 
+ }) # examplesIf
> models %>% summarise(broom::glance(model))
Error in `summarise()`:
ℹ In argument: `broom::glance(model)`.
ℹ In row 1.
Caused by error in `ll()`:
! could not find function "ll"
Backtrace:
     ▆
  1. ├─(if (getRversion() >= "3.4") withAutoprint else force)(...)
  2. │ └─base::source(...)
  3. │   ├─base::withVisible(eval(ei, envir))
  4. │   └─base::eval(ei, envir)
  5. │     └─base::eval(ei, envir)
  6. ├─models %>% summarise(broom::glance(model))
  7. ├─dplyr::summarise(., broom::glance(model))
  8. ├─dplyr:::summarise.rowwise_df(., broom::glance(model))
  9. │ └─dplyr:::summarise_cols(.data, dplyr_quosures(...), by, "summarise")
 10. │   ├─base::withCallingHandlers(...)
 11. │   └─dplyr:::map(quosures, summarise_eval_one, mask = mask)
 12. │     └─base::lapply(.x, .f, ...)
 13. │       └─dplyr (local) FUN(X[[i]], ...)
 14. │         └─mask$eval_all_summarise(quo)
 15. │           └─dplyr (local) eval()
 16. ├─broom::glance(model)
 17. ├─broom:::glance.lm(model)
 18. │ ├─base::with(...)
 19. │ └─base::with.default(...)
 20. │   └─base::eval(substitute(expr), data, enclos = parent.frame())
 21. │     └─base::eval(substitute(expr), data, enclos = parent.frame())
 22. │       └─tibble::tibble(...)
 23. │         └─tibble:::tibble_quos(xs, .rows, .name_repair)
 24. │           └─rlang::eval_tidy(xs[[j]], mask)
 25. ├─stats::AIC(x)
 26. ├─stats:::AIC.default(x)
 27. └─base::.handleSimpleError(...)
 28.   └─dplyr (local) h(simpleError(msg, call))
 29.     └─dplyr (local) handler(cnd)
 30.       └─rlang::abort(message, class = error_class, parent = parent, call = error_call)
Execution halted