tidybayes: n_prefix – R documentation

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n_prefix

Prefix function generator for composing dimension index columns

Description

Generates a function for generating names of index columns for factors in compose_data() by prefixing a character vector to the original column name.

Usage

n_prefix(prefix)

Arguments

prefix

Character vector to be prepended to column names by compose_data() to create index columns. Typically something like "n" (that is the default used in the .n_name argument of compose_data()).

Returns a function. The function returned takes a character vector, name and returns paste0(prefix, "_", name), unless name is empty, in which case it will return prefix.

n_prefix("n") is the default method that compose_data() uses to generate column names for variables storing the number of levels in a factor. Under this method, given a data frame df with a factor column "foo" containing 5 levels, the results of compose_data(df) will include an element named "n" (the result of n_prefix("n")("")) equal to the number of rows in df and an element named "n_foo" (the result of n_prefix("n")("foo")) equal to the number of levels in df$foo.

Examples

library(magrittr)

df = data.frame(
  plot = factor(paste0("p", rep(1:8, times = 2))),
  site = factor(paste0("s", rep(1:4, each = 2, times = 2)))
)

# without changing `.n_name`, compose_data() will prefix indices
# with "n" by default
df %>%
  compose_data()

# you can use n_prefix() to define a different prefix (e.g. "N"):
df %>%
  compose_data(.n_name = n_prefix("N"))

tidybayes

Tidy Data and 'Geoms' for Bayesian Models

v2.3.1

GPL (>= 3)

Authors

Matthew Kay [aut, cre], Timothy Mastny [ctb]

Initial release

2020-10-30