where does the null come from?

Hi!

    m = matrix(1:4, 2)

    apply(m, 1, cat, '\n')
    # 1 2
    # 3 4
    # NULL

why the null?

Could it be the return value of 'cat'. See ?cat, where:

---snip ---
Value
 None (invisible NULL).
---snip ---

Kind regrads,
Kimmo