repeat vector

[Niels Henrik Bruun]

Hi
I was quite sure I've seen a way to repeat vectors in mata the same way as in R with:

> rep(c(0,1), 5)
 [1] 0 1 0 1 0 1 0 1 0 1

I searched for a while without luck, but then I figured it out:

. mata J(1, 4, (0,1))
       1   2   3   4   5   6   7   8
    +---------------------------------+
  1 |  0   1   0   1   0   1   0   1  |
    +---------------------------------+

For other lost soules I leave my findings.
The J function is quite powerfull.
Have a nice weekend

[Nick Cox]

See also http://www.stata-journal.com/sjpdf.h...iclenum=pr0043

[Niels Henrik Bruun]

One can also expand (eg 4 times) a set of values ("a", "b") by combining the J function with the vec function:

. mata vec(J(4,1, ("a",  "b")))'
       1   2   3   4   5   6   7   8
    +---------------------------------+
  1 |  a   a   a   a   b   b   b   b  |
    +---------------------------------+

[wbuchanan]

Niels Henrik Bruun it doesn't generalize to different types just yet, but I put something together like this to handle "recycling" colors in brewscheme. You can view the source in the repository. Similar to the R functionality it will continue to repeat the pattern of values from beginning to end until matching the appropriate length. I suppose I could make it a bit more generalizable by using transmorphic matrix parameters, but I didn't really spend to much time on it after I was able to get what I needed done.