Collapse repeated columns into rows [duplicate]

Answer 1

Convert the input data.frame to a list and split the columns into groups according to their common column names. Then unlist each group of columns to produce a single column in each group and convert back to a data.frame. (This also works if there is more than one row in DF.)

as.data.frame(lapply(split(as.list(DF), names(DF)), unlist))

giving:

  Rating  Title Year
1    6.7 Movie1 1997
2    8.2 Movie2 1987
3    7.1 Movie3 2009

Note: We assumed this input:

Lines <- "Title   Year  Rating  Title    Year  Rating  Title    Year  Rating
Movie1 1997  6.7     Movie2  1987  8.2     Movie3  2009  7.1"
DF <- read.table(text = Lines, header = TRUE, check.names = FALSE, as.is = TRUE)