[Solved] Join columns of the same data.frame

df <- setNames(data.frame(matrix(, nrow = 100, ncol = 2)), c("V1", "V2"))
df$V1 <- "a, b, c, d, e"
df$V2 <- "b, c, a, b, e"
df$V3 <- paste(df$V1, df$V2, sep = ", ")

Hope this helps.