cells: The experimental cells of a design

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

The experimental cells of a design

Description

Return the experimental cells that are in a model term as a table. Experimental cells represent unique combinations of factor levels in the design. For example, if a design has factors A (levels: a1, a2) and B (levels: b1, b2), the cells would be: a1:b1, a1:b2, a2:b1, a2:b2.

Usage

cells(x, ...)

## S3 method for class 'event_factor'
cells(x, drop.empty = TRUE, ...)

## S3 method for class 'event_term'
cells(x, drop.empty = TRUE, ...)

## S3 method for class 'covariate_convolved_term'
cells(x, ...)

Arguments

x	An event_term object.
...	Additional arguments.
drop.empty	Logical; if TRUE, remove cells with no events.

Value

A tibble containing the experimental cells with attributes:

count

Number of events in each cell

rownames

Cell names when cells have multiple factors

A list of data frames containing the cells.

A tibble containing the cells with a "count" attribute.

See Also

event_term(), event_model()

Examples

# Create a simple factorial design
evlist <- list(
  fac1 = factor(c("A", "B", "A", "B")),
  fac2 = factor(c("1", "1", "2", "2"))
)

# Create an event term
eterm <- event_term(
  evlist,
  onsets = 1:4,
  blockids = rep(1, 4)
)

# Get the experimental cells
cells(eterm)  # Returns cells: A:1, A:2, B:1, B:2

# Create an event model
event_data <- data.frame(
  fac = c("a", "B", "A", "B"),
  onsets = c(1, 10, 20, 80),
  run = c(1, 1, 1, 1)
)
sframe <- sampling_frame(blocklens = 50, TR = 2)
evmodel <- event_model(
  onsets ~ hrf(fac),
  data = event_data,
  block = ~run,
  sampling_frame = sframe
)

# Get cells from the model
cells(evmodel)
evlist <- list(fac1 = factor(c("A", "B", "A", "B")), 
               fac2 = factor(c("1", "1", "2", "2")))
eterm <- event_term(evlist, onsets = 1:4, blockids = rep(1, 4))
cells(eterm)

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