Can't figure out how to add a summary function to count the rows in a group...
Try using the length() function.
I got length() to work as a grand summary:
library(tidyverse)
library(gt)
exibble %>% select(group, char, date, num) %>%
gt(groupname_col = "group") %>%
summary_rows(
groups = NULL,
columns = vars(num),
fns = list(len = ~length(.)
))
| char | date | num | |
|---|---|---|---|
| grp_a | |||
| apricot | 2015-01-15 | 1.111e-01 | |
| banana | 2015-02-15 | 2.222e+00 | |
| coconut | 2015-03-15 | 3.333e+01 | |
| durian | 2015-04-15 | 4.444e+02 | |
| grp_b | |||
| NA | 2015-05-15 | 5.550e+03 | |
| fig | 2015-06-15 | NA | |
| grapefruit | NA | 7.770e+05 | |
| honeydew | 2015-08-15 | 8.880e+06 | |
| len | — | — | 8.00 |
Created on 2020-04-13 by the reprex package (v0.3.0)
But when groups = T, no summary is produced:
library(tidyverse)
library(gt)
exibble %>% select(group, char, date, num) %>%
gt(groupname_col = "group") %>%
summary_rows(
groups = T,
columns = vars(group),
fns = list(len = ~length(.)
))
| char | date | num |
|---|---|---|
| grp_a | ||
| apricot | 2015-01-15 | 1.111e-01 |
| banana | 2015-02-15 | 2.222e+00 |
| coconut | 2015-03-15 | 3.333e+01 |
| durian | 2015-04-15 | 4.444e+02 |
| grp_b | ||
| NA | 2015-05-15 | 5.550e+03 |
| fig | 2015-06-15 | NA |
| grapefruit | NA | 7.770e+05 |
| honeydew | 2015-08-15 | 8.880e+06 |
Created on 2020-04-13 by the reprex package (v0.3.0)
With the following:
you are attempting to place the summary result in a column that is hidden. Try using columns = vars(num) instead.
No, I tried that:
library(tidyverse)
library(gt)
exibble %>% select(group, char, date, num) %>%
gt(groupname_col = "group") %>%
summary_rows(
groups = T,
columns = vars(num),
fns = list(len = ~length(.)
))
| char | date | num |
|---|---|---|
| grp_a | ||
| apricot | 2015-01-15 | 1.111e-01 |
| banana | 2015-02-15 | 2.222e+00 |
| coconut | 2015-03-15 | 3.333e+01 |
| durian | 2015-04-15 | 4.444e+02 |
| grp_b | ||
| NA | 2015-05-15 | 5.550e+03 |
| fig | 2015-06-15 | NA |
| grapefruit | NA | 7.770e+05 |
| honeydew | 2015-08-15 | 8.880e+06 |
Created on 2020-04-13 by the reprex package (v0.3.0)
It looks like there is a bug where the summary rows don't get built if there is no stub. I'll file an issue shortly to ensure this gets fixed. As a temporary workaround, this should work:
library(tidyverse)
library(gt)
exibble %>%
select(group, char, date, num) %>%
mutate(stub = rep(" ", nrow(.))) %>%
gt(groupname_col = "group", rowname_col = "stub") %>%
summary_rows(
groups = TRUE,
columns = vars(num),
fns = list(len = ~length(.)
)
)
That creates a column with space characters before using gt(), then that stub column is specified in the gt() call.
Thanks for the workaround. As you note, it works, except that the length function only works if the your dataset has a disposable numeric variable to use with the columns parameter, and the count comes out with two trailing zeros.
As you work on a fix, I'd suggest that counting the rows in a group would be a common use case for a summary_rows function.
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