Repeat vector to fill down column in data frame

Question

Seems like this very simple maneuver used to work for me, and now it simply doesn\'t. A dummy version of the problem:

df <- data.frame(x = 1:5) # create simpl         


        

Answer 1

If the vector can be evenly recycled, into the data.frame, you do not get and error or a warning:

df <- data.frame(x = 1:10)
df$z <- 1:5

This may be what you were experiencing before.

You can get your vector to fit as you mention with rep_len:

df$y <- rep_len(1:3, length.out=10)

This results in

df
    x z y
1   1 1 1
2   2 2 2
3   3 3 3
4   4 4 1
5   5 5 2
6   6 1 3
7   7 2 1
8   8 3 2
9   9 4 3
10 10 5 1

Note that in place of rep_len, you could use the more common rep function:

df$y <- rep(1:3,len=10)

From the help file for rep:

rep.int and rep_len are faster simplified versions for two common cases. They are not generic.