levels: levels

In bbuchsbaum/fmrireg: R package for the anlysis of fmri data

levels

Description

Extract the levels of a term. For categorical terms (event_factor), this returns the factor levels. For continuous terms (event_variable), this returns the variable name. For matrix terms, this returns the column names. For event terms with multiple factors, this returns the interaction of all factor levels.

Usage

levels(x)

Arguments

x	The term (typically an event_factor, event_variable, event_matrix, or event_term)

Value

A character vector containing:

• For event_factor: The factor levels

• For event_variable: The variable name

• For event_matrix: The column names

• For event_term: The interaction of factor levels for categorical variables

See Also

event_term(), event_factor(), event_variable()

Other term_properties: elements()

Examples

# Factor event
event_data <- data.frame(
  stimulus = factor(c("face", "house", "face", "house")),
  onsets = c(1, 10, 20, 30),
  run = c(1, 1, 1, 1)
)
fac_term <- event_term(
  list(stimulus = event_data$stimulus),
  onsets = event_data$onsets,
  blockids = event_data$run
)
levels(fac_term)  # Returns: c("face", "house")

# Multiple factor event
event_data$location <- factor(c("left", "right", "left", "right"))
multi_term <- event_term(
  list(
    stimulus = event_data$stimulus,
    location = event_data$location
  ),
  onsets = event_data$onsets,
  blockids = event_data$run
)
levels(multi_term)  # Returns: c("face:left", "house:left", "face:right", "house:right")

bbuchsbaum/fmrireg documentation built on March 1, 2025, 11:20 a.m.