Skip to contents

Transform wide format data sets into the long format necessary for eatRep analyses

wideToLong.rd

Data from large-scale assessments often are provided in the wide format. This function easily transform data into the long format required by eatRep.

Usage

wideToLong (datWide, noImp, imp, multipleColumns = TRUE, variable.name = "variable",
            value.name = "value")

Arguments

datWide

Data set in the wide format, i.e. one row per person

noImp

character vector of non-imputed variables which are desired for following analyses

imp

Named list of character vectors which include the imputed variables which are desired for following analyses

multipleColumns

Logical: use one column for each imputed variable (if more than one imputed variable is used)? Alternatively, only one column for all imputed variables is used (this is the default behavior of the melt function from the reshape2 package).

variable.name

Applies only if multipleColumns = "FALSE": name of variable used to store measured variable names

value.name

Applies only if multipleColumns = "FALSE": name of variable used to store values

Value

A data.frame in the long format.

Author

Sebastian Weirich

Examples

### create arbitrary wide format large-scale assessment data for two
### subjects, each with three imputations
datWide <- data.frame ( id = paste0("P",1:5), weight = abs(rnorm(5,10,1)),
           country = c("USA", "BRA", "TUR", "GER", "AUS"),
           sex = factor(c("female", "male", "female", "female", "male")),
           matrix(data = rnorm(n=15, mean = 500, sd = 75),
                  nrow=5, dimnames = list(NULL, paste0("mat.pv", 1:3))),
           matrix(data = rnorm(n=15, mean = 480, sd = 80),
                  nrow=5, dimnames = list(NULL, paste0("sci.pv", 1:3))),
           stringsAsFactors=FALSE)
datLong <- wideToLong(datWide = datWide, noImp = c("id", "weight", "country", "sex"),
             imp = list ( math = paste0("mat.pv", 1:3),
                   science = paste0("sci.pv", 1:3)))
datLong2<- wideToLong(datWide = datWide, noImp = c("id", "weight", "country", "sex"),
             imp = list ( math = paste0("mat.pv", 1:3),
                   science = paste0("sci.pv", 1:3)),
             multipleColumns = FALSE, variable.name = "varName",
             value.name = "val")