Please help me with the following matter
I have a wide data frame that I need to reshape.
This is the df I have
mydf <- data.frame(date=1983:1985,January=c(5,7,8),February=c(12,18,19))
mydf
this is the output I need
output <- data.frame(date=rep(c(1983,1984,1985),each=2),Month=rep(c("January","February"),3),Value=c(5,12,7,18,8,19))
output