add_contrast: Add a contrast to a data frame

In faux: Simulation for Factorial Designs

Add a contrast to a data frame

Description

Add a contrast to a data frame

Usage

add_contrast(
  data,
  col,
  contrast = c("anova", "sum", "treatment", "helmert", "poly", "difference"),
  levels = NULL,
  ...,
  add_cols = TRUE,
  colnames = NULL
)

Arguments

data	the data frame
col	the column to recode
contrast	the contrast to recode to
levels	the levels of the factor in order
...	arguments to pass to the contrast function (base or omit)
add_cols	whether to just add the contrast to the existing column or also to create new explicit columns in the dataset (default)
colnames	optional list of column names for the added contrasts

Value

the data frame with the recoded column and added columns (if add_cols == TRUE)

Examples

df <- sim_design(between = list(time = 1:6), plot = FALSE) %>%
   add_contrast("time", "poly")

# test all polynomial contrasts
lm(y ~ time, df) %>% broom::tidy()

# test only the linear and quadratic contrasts
lm(y ~ `time^1` + `time^2`, df) %>% broom::tidy()

faux documentation built on April 3, 2025, 7:44 p.m.