longToWide: Reshape from long to wide

Description

Reshapes a data frame from long form (one row per observation) to wide form (one row per subject), using a formula to specify the structure.

Usage

longToWide(data, formula, sep = "_")

Value

A wide-form data frame with one row per subject (or experimental unit). Column names for the repeated measures follow the naming convention used by wideToLong: the measure name followed by the within-subject factor level(s), separated by sep.

Arguments

data: A long-form data frame with one row per observation.
formula: A two-sided formula of the form measure ~ within, listing the measured variable(s) on the left and the within-subject variable(s) on the right. All other variables in data are treated as between-subject variables. Multiple variables are supported on each side, e.g. rt + accuracy ~ day + session.
sep: The separator string used to construct wide-form variable names. Defaults to "_". For example, with sep = "_" and a measure called accuracy at levels t1 and t2, the output columns are named accuracy_t1 and accuracy_t2.

Details

This function is the companion to wideToLong. It reshapes a long-form data frame into wide form by spreading the within-subject observations across columns, with column names constructed from the measure name and factor level(s) joined by sep.

Examples

Run this code

long <- data.frame(
  id       = c(1, 2, 3, 1, 2, 3, 1, 2, 3),
  time     = c("t1", "t1", "t1", "t2", "t2", "t2", "t3", "t3", "t3"),
  accuracy = c(.50, .03, .72, .94, .63, .49, .78, .71, .16)
)

longToWide(long, accuracy ~ time)