{reshape}R Documentation

Melt a data frame


Melt a data frame into form suitable for easy casting.

Usage, id.var, measure.var, variable_name = "variable", na.rm = !, = TRUE, ...)


data Data set to melt
id.var Id variables. If blank, will use all non measure.var variables
measure.var Measured variables. If blank, will use all non id.var variables
variable_name Name of the variable that will store the names of the original variables
na.rm Should NAs be removed from the data set? Old argument name, now deprecated


You need to tell melt which of your variables are id variables, and which are measured variables. If you only supply one of id.var and measure.var, melt will assume the remainder of the variables in the data set belong to the other. If you supply neither, melt will assume integer and factor variables are id variables, and all other are measured.


molten data


Hadley Wickham <>

See Also


names(airquality) <- tolower(names(airquality))
melt(airquality, id=c("month", "day"))
names(ChickWeight) <- tolower(names(ChickWeight))
melt(ChickWeight, id=2:4)

[Package reshape version 0.8.0 Index]