Expand data.frame by adding new column

Question

Here an example of my data.frame(s):

df = data.frame(x=c(1871:1872))
df2 = data.frame(y=c(1:3))

How can I expand df with df2 observations?

Desired output:

x     y
1871  1
1871  2
1871  3
1872  1
1872  2
1872  3

I couldn't find any solution yet. Thanks

Answer 1

One way with lapply:

do.call(rbind, lapply(df$x, function(z) {
  cbind(z, df2)
}))
#     z y
#1 1871 1
#2 1871 2
#3 1871 3
#4 1872 1
#5 1872 2
#6 1872 3

lapply iterates over df$x and cbinds the whole df2 to each element of df$x. do.call combines everything together in one data.frame.