RcmdrMisc (version 2.9-1)

reshapeL2W: Reshape Repeated-Measures Data from Long to Wide Format

Description

A simple front-end to the standard R reshape function. The data are assumed to be in "long" format, with several rows for each subject.

Usage

reshapeL2W(data, within, id, varying, ignore)

Value

a data frame in "wide" format, with one row for each subject, columns representing the between subjects factors, and columns for the occasion-varying variable(s) for each combination of within-subjects factors.

Arguments

data

a data frame in long format.

within

a character vector of names of the within-subjects factors in the long form of the data; there must be at least one within-subjects factor.

id

the (character) name of the variable representing the subject identifier in the long form of the data set; that is, rows with the same id belong to the same subject.

varying

a character vector of names of the occasion-varying variables in the long form of the data; there must be at least one such variable, and typically there will be just one, an occasion-varying response variable.

ignore

an optional character vector of names of variables in the long form of the data to exclude from the wide data set.

Author

John Fox

Details

Between-subjects variables don't vary by occasions for each subject. Variables that aren't listed explicitly in the arguments to the function are assumed to be between-subjects variables, and a warning is printed if their values aren't invariant for each subject (see the ignore argument).

Within-subjects factors vary by occasions for each subject, and it is assumed that the within-subjects design is regular, completely crossed, and balanced, so that the same combinations of within-subjects factors are observed for each subject.

Occasion-varying variables, as their name implies, (potentially) vary by occasions for each subject, and include one or more "response" variables, possibly along with occasion-varying covariates; these variables can be factors as well as numeric variables.

The data are reshaped so that there is one row per subject, with columns for the between-subjects variables, and each occasion-varying variable as multiple columns representing the combinations of levels of the within-subjects factors. The names of the columns for the occasion-varying variables are composed from the combinations of levels of the within-subjects factors and from the names of the occasion-varying variables. If a subject in the long form of the data set lacks any combination of levels of within-subjects factors, he or she is excluded (with a warning) from the wide form of the data.

See Also

reshape, OBrienKaiser, OBrienKaiserLong.

Examples

if (require(carData)){
  OBW <- reshapeL2W(OBrienKaiserLong,
                    within=c("phase", "hour"), 
                    id="id", varying="score")
  brief(OBW)
  # should be the same as OBrienKaiser in the carData package:
  all.equal(OBrienKaiser, OBW, check.attributes=FALSE)
}