count.duckplyr_df {duckplyr} | R Documentation |
Count the observations in each group
Description
This is a method for the dplyr::count()
generic.
See "Fallbacks" section for differences in implementation.
count()
lets you quickly count the unique values of one or more variables:
df %>% count(a, b)
is roughly equivalent to
df %>% group_by(a, b) %>% summarise(n = n())
.
count()
is paired with tally()
, a lower-level helper that is equivalent
to df %>% summarise(n = n())
. Supply wt
to perform weighted counts,
switching the summary from n = n()
to n = sum(wt)
.
Usage
## S3 method for class 'duckplyr_df'
count(
x,
...,
wt = NULL,
sort = FALSE,
name = NULL,
.drop = group_by_drop_default(x)
)
Arguments
x |
A data frame, data frame extension (e.g. a tibble), or a lazy data frame (e.g. from dbplyr or dtplyr). |
... |
< |
wt |
<
|
sort |
If |
name |
The name of the new column in the output. If omitted, it will default to |
.drop |
Handling of factor levels that don't appear in the data, passed
on to For
|
Fallbacks
There is no DuckDB translation in count.duckplyr_df()
with complex expressions in
...
,with
.drop = FALSE
,with
sort = TRUE
.
These features fall back to dplyr::count()
, see vignette("fallback")
for details.
See Also
Examples
library(duckplyr)
count(mtcars, am)