K - 12 characters
Let's take the rosetta-stoning seriously, and compare Kdb+'s K4 with the canonical J solution (*/~1+i.9
):
a*/:\:a:1+!9
1 2 3 4 5 6 7 8 9
2 4 6 8 10 12 14 16 18
3 6 9 12 15 18 21 24 27
4 8 12 16 20 24 28 32 36
5 10 15 20 25 30 35 40 45
6 12 18 24 30 36 42 48 54
7 14 21 28 35 42 49 56 63
8 16 24 32 40 48 56 64 72
9 18 27 36 45 54 63 72 81
J's "table" operator (/
) equals the K "each-left each-right" (/:\:
) idiom. We don't have J's extremely handy "reflexive" operator (~
) in K, so we have to pass a
as both left and right argument.