Merge multiple data tables with duplicate column names

Question

I am trying to merge (join) multiple data tables (obtained with fread from 5 csv files) to form a single data table. I get an error when I try to merge 5 data tables, but wo

Answer 1

Another way of doing this:

dts <- list(DT1, DT2, DT3, DT4, DT5)

names(dts) <- paste("y", seq_along(dts), sep="")
data.table::dcast(rbindlist(dts, idcol="id"), x ~ id, value.var = "y")

#   x y1 y2 y3 y4 y5
#1: a 10 11 12 13 14
#2: b 11 12 13 14 15
#3: c 12 13 14 15 16
#4: d 13 14 15 16 17
#5: e 14 15 16 17 18
#6: f 15 16 17 18 19

The package name in "data.table::dcast" is added to ensure that the call returns a data table and not a data frame even if the "reshape2" package is loaded as well. Without mentioning the package name explicitly, the dcast function from the reshape2 package might be used which works on a data.frame and returns a data.frame instead of a data.table.