Count observations by group — count.tidymatrix • tidymatrix

Count the number of observations in each group, aggregating the matrix. Returns a tidymatrix (not a tibble).

Usage

# S3 method for class 'tidymatrix'
count(
  x,
  ...,
  wt = NULL,
  sort = FALSE,
  name = NULL,
  .drop = TRUE,
  .matrix_fn = NULL,
  .matrix_args = list()
)

Arguments

x: A tidymatrix object
...: Variables to group by
wt: Frequency weights (not yet implemented)
sort: If TRUE, sort output in descending order of n
name: Name of count column (default: "n")
.drop: Drop groups with zero observations
.matrix_fn: Function to aggregate matrix values. Default is mean for numeric matrices. Required for non-numeric matrices.
.matrix_args: List of additional arguments to pass to .matrix_fn

Value

A tidymatrix object with counts and aggregated matrix

Examples

library(dplyr, warn.conflicts = FALSE)
mat <- matrix(rnorm(20), nrow = 10, ncol = 2)
row_data <- data.frame(
  id = 1:10,
  group = rep(c("A", "B"), each = 5),
  subgroup = rep(c("x", "y"), 5)
)
tm <- tidymatrix(mat, row_data)

# Count by single variable
tm |>
  activate(rows) |>
  count(group)
#> # A tidymatrix: 2 x 2 matrix
#> # Active: rows
#> #
#> # Row data: 2 rows x 2 columns
#> # Column data: 2 rows x 1 columns
#> #
#> # Active data (rows):
#>   group n
#> 1     A 5
#> 2     B 5

# Count by multiple variables
tm |>
  activate(rows) |>
  count(group, subgroup)
#> # A tidymatrix: 4 x 2 matrix
#> # Active: rows
#> #
#> # Row data: 4 rows x 3 columns
#> # Column data: 2 rows x 1 columns
#> #
#> # Active data (rows):
#>   group subgroup n
#> 1     A        x 3
#> 2     A        y 2
#> 3     B        x 2
#> 4     B        y 3

# Use different aggregation for matrix
tm |>
  activate(rows) |>
  count(group, .matrix_fn = median)
#> # A tidymatrix: 2 x 2 matrix
#> # Active: rows
#> #
#> # Row data: 2 rows x 2 columns
#> # Column data: 2 rows x 1 columns
#> #
#> # Active data (rows):
#>   group n
#> 1     A 5
#> 2     B 5