melt_wide: Melt Wide data.tables into Long data.tables
In mrdwab/SOfun: Functions From Answers to R Questions on Stack Overflow

Description Usage Arguments Value Author(s) References Examples

Reshapes double and tripple wide data.tables to long data.tables

1	melt_wide(data, id.vars, new.names)

`data`	The input `data.frame`
`id.vars`	ID variables
`new.names`	The new names for the resulting columns

A long data.table

Ananda Mahto

http://stackoverflow.com/a/10170630/1270695

triplewide <- structure(list(ID = 1:4,
                             w1d1t1 = c(4L, 3L, 2L, 2L),
                             w1d1t2 = c(5L, 4L, 3L, 3L),
                             w1d2t1 = c(6L, 5L, 5L, 4L),
                             w1d2t2 = c(5L, 4L, 5L, 2L),
                             w2d1t1 = c(6L, 5L, 4L, 3L),
                             w2d1t2 = c(5L, 4L, 5L, 5L),
                             w2d2t1 = c(6L, 3L, 6L, 3L),
                             w2d2t2 = c(7L, 4L, 3L, 2L)),
                             .Names = c("ID", "w1d1t1", "w1d1t2",
                             "w1d2t1", "w1d2t2", "w2d1t1", "w2d1t2",
                             "w2d2t1", "w2d2t2"),
                             class = "data.frame",
                             row.names = c(NA, -4L))
triplewide
triplewide.long <- melt_wide(triplewide, id.vars="ID",
                            new.names=c("week", "day", "trial"))
triplewide.long
data.table::dcast(triplewide.long, ID + week + day ~ trial)