add_count: Add a count column to the data frame

In mtfairbanks/gdt: Tidy Interface to 'data.table'

Add a count column to the data frame

Description

Add a count column to the data frame.

df %>% add_count(a, b) is equivalent to using df %>% mutate(n = n(), .by = c(a, b))

Usage

add_count(.df, ..., wt = NULL, sort = FALSE, name = NULL)

add_tally(.df, wt = NULL, sort = FALSE, name = NULL)

Arguments

.df	A data.frame or data.table
...	Columns to group by. tidyselect compatible.
wt	Frequency weights. Can be NULL or a variable: If NULL (the default), counts the number of rows in each group. If a variable, computes sum(wt) for each group.
sort	If TRUE, will show the largest groups at the top.
name	The name of the new column in the output. If omitted, it will default to n.

Examples

df <- data.table(
  a = c("a", "a", "b"),
  b = 1:3
)

df %>%
  add_count(a)

mtfairbanks/gdt documentation built on April 12, 2024, 6:51 p.m.