Both k language and numpy are array language implementations for numeric-intensive computation. Well, they’re of course more, you can read about them following the links above. k numpy +a transpose(a) a+3 a+3 -a -a a-3 a-3 *a a[0] a*3 a*3 a*b a*b %a 1./a a%3 a/3. &a ??? a&3 where(a<3,a,3) |a a[::-1] a|b where(a>b,a,b) 4|a where(a>4,a,4) < a argsort(a)[::-1] a < b a < b >a argsort(a) a>b a>b =a NA (not rectangle result) a=3 a==b \^a shape(a) a\^3 a**3 !3 arange(3) 3!a roll(a,3) a!3 a%3 ~a a==0 a~b any(a==b) ,3 array([3]) a,b hstack([a,b]) #a size(a) 3#a resize(a, 3) 2 3#a resize(a, [2,3]) _ a floor(a) 3_ a a[3:] 2 3_ a NA (not rectangle result) $a asarray(a,dtype=str) 3$a Use standard python formatting ?a unique(a) a?3 nonzero(a==3)[0][0] @a not ndim(a) a@3 a[3] And some often used expressions a[&a>b] a[a>b] #\^a rank(a) (#a)>a?3 any(a==3) a[>a] sort(a)