group_by logs incorrect value

[aniruhil]

Great idea! I was planning on using it to teach tidy verse next week and noticed group_by() throws an incorrect value. I am using your code example too, so not sure what is going on here. sessionInfo follows, in case that helps.

library(dplyr)
#> 
#> Attaching package: 'dplyr'
#> The following objects are masked from 'package:stats':
#> 
#>     filter, lag
#> The following objects are masked from 'package:base':
#> 
#>     intersect, setdiff, setequal, union
library(tidylog)
#> 
#> Attaching package: 'tidylog'
#> The following objects are masked from 'package:dplyr':
#> 
#>     anti_join, distinct, filter, filter_all, filter_at, filter_if,
#>     full_join, group_by, group_by_all, group_by_at, group_by_if,
#>     inner_join, left_join, mutate, mutate_all, mutate_at,
#>     mutate_if, right_join, select, select_all, select_at,
#>     select_if, semi_join, transmute, transmute_all, transmute_at,
#>     transmute_if
#> The following object is masked from 'package:stats':
#> 
#>     filter
summary <- mtcars %>%
  select(mpg, cyl, hp) %>%
  filter(mpg > 15) %>%
  mutate(mpg_round = round(mpg)) %>%
  group_by(cyl, mpg_round) %>%
  tally() %>%
  filter(n >= 1)
#> select: dropped 8 variables (disp, drat, wt, qsec, vs, …) 
#> filter: removed 6 rows (19%) 
#> mutate: new variable 'mpg_round' with 15 unique values and 0% NA 
#> group_by: 0 groups [] 
#> filter: no rows removed


sessionInfo()
#> R version 3.5.2 (2018-12-20)
#> Platform: x86_64-apple-darwin15.6.0 (64-bit)
#> Running under: macOS Sierra 10.12.6
#> 
#> Matrix products: default
#> BLAS: /Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRblas.0.dylib
#> LAPACK: /Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRlapack.dylib
#> 
#> locale:
#> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> loaded via a namespace (and not attached):
#>  [1] compiler_3.5.2  magrittr_1.5    tools_3.5.2     htmltools_0.3.6
#>  [5] yaml_2.2.0      Rcpp_1.0.0      stringi_1.2.4   rmarkdown_1.11 
#>  [9] highr_0.7       knitr_1.21      stringr_1.3.1   xfun_0.4       
#> [13] digest_0.6.18   evaluate_0.12

[elbersb]

That's indeed odd. Just a hunch: Could you upgrade your glue package and try again?

[aniruhil]

Force-updated glue (though the system threw the expected "Skipping install of 'glue' from a github remote, the SHA1 (8188cea6) has not changed since last install." message. Same result:

group_by: 0 groups [] 

[elbersb]

Does it work with other data frames?

Could you run this and post the output?

summary <- mtcars %>%
  select(mpg, cyl, hp) %>%
  filter(mpg > 15) %>%
  mutate(mpg_round = round(mpg)) %>%
  group_by(cyl, mpg_round)
str(summary)

[aniruhil]

summary <- mtcars %>%
   select(mpg, cyl, hp) %>%
   filter(mpg > 15) %>%
   mutate(mpg_round = round(mpg)) %>%
   group_by(cyl, mpg_round)

select: dropped 8 variables (disp, drat, wt, qsec, vs, …)
filter: removed 6 rows (19%)
mutate: new variable 'mpg_round' with 15 unique values and 0% NA
group_by: 0 groups []

str(summary)

Classes ‘grouped_df’, ‘tbl_df’, ‘tbl’ and 'data.frame':	26 obs. of  4 variables:
 $ mpg      : num  21 21 22.8 21.4 18.7 18.1 24.4 22.8 19.2 17.8 ...
 $ cyl      : num  6 6 4 6 8 6 4 4 6 6 ...
 $ hp       : num  110 110 93 110 175 105 62 95 123 123 ...
 $ mpg_round: num  21 21 23 21 19 18 24 23 19 18 ...
 - attr(*, "groups")=Classes ‘tbl_df’, ‘tbl’ and 'data.frame':	17 obs. of  3 variables:
  ..$ cyl      : num  4 4 4 4 4 4 4 4 4 6 ...
  ..$ mpg_round: num  21 22 23 24 26 27 30 32 34 18 ...
  ..$ .rows    :List of 17
  .. ..$ : int 26
  .. ..$ : int 17
  .. ..$ : int  3 8
  .. ..$ : int 7
  .. ..$ : int 22
  .. ..$ : int 21
  .. ..$ : int  15 23
  .. ..$ : int 14
  .. ..$ : int 16
  .. ..$ : int  6 10
  .. ..$ : int 9
  .. ..$ : int 25
  .. ..$ : int  1 2 4
  .. ..$ : int  13 19
  .. ..$ : int  11 18 24
  .. ..$ : int 12
  .. ..$ : int  5 20
  ..- attr(*, ".drop")= logi TRUE

[aniruhil]

closed it by accident; sorry!!

also tried it with the diamonds data:

diamonte <- diamonds %>%
   filter(carat > 1) %>%
   group_by(cut)

filter: removed 36438 rows (68%)
group_by: 0 groups []

[elbersb]

Are you running a development version of dplyr?

library(dplyr)
sessionInfo()

[aniruhil]

dplyr version is 0.8.0, release candidate scheduled for Feb 1

[1] ggplot2_3.1.0.9000 reprex_0.2.1 tidylog_0.1.0 dplyr_0.8.0

If I rollback to dplyr 0.7.8 then group_by() works. So there is something in 0.8.0 that is causing the break

[elbersb]

08d11d2 should fix this. Can you reinstall tidylog and try it out?

[aniruhil]

08d11d2 works like a charm. Thanks for the quick fix, and this immensely useful package that will benefit all tidyverse learners.

Have a great weekend!

[elbersb]

thanks for the report! Now we already support dplyr 0.8 before the release :)