summarise.dtplyr_step {dtplyr} | R Documentation |
Summarise each group to one row
Description
This is a method for the dplyr summarise()
generic. It is translated to
the j
argument of [.data.table
.
Usage
## S3 method for class 'dtplyr_step'
summarise(.data, ..., .groups = NULL)
Arguments
.data |
A lazy_dt() .
|
... |
<data-masking > Name-value pairs of summary
functions. The name will be the name of the variable in the result.
The value can be:
A vector of length 1, e.g. min(x) , n() , or sum(is.na(y)) .
A vector of length n , e.g. quantile() .
A data frame, to add multiple columns from a single expression.
|
.groups |
Grouping structure of the result.
"drop_last": dropping the last level of grouping. This was the
only supported option before version 1.0.0.
"drop": All levels of grouping are dropped.
"keep": Same grouping structure as .data .
When .groups is not specified, it defaults to "drop_last".
In addition, a message informs you of that choice, unless the result is ungrouped,
the option "dplyr.summarise.inform" is set to FALSE ,
or when summarise() is called from a function in a package.
|
Examples
library(dplyr, warn.conflicts = FALSE)
dt <- lazy_dt(mtcars)
dt %>%
group_by(cyl) %>%
summarise(vs = mean(vs))
dt %>%
group_by(cyl) %>%
summarise(across(disp:wt, mean))
[Package
dtplyr version 1.2.2
Index]