- Compression: use a bit vector to select out elements of another vector.
- http://stackoverflow.com/questions/22742281/how-do-i-do-in-f-what-would-be-called-compression-in-apl?rq=1
a ← ι10
b ← (~a ∊ 4 6) / aa = ^10
b = select (not (a in? [4, 6])) a
b = not (a in? [4, 6]) // a
b = a \\ not (a in? [4, 6])
b = a # not (a in? [4, 6])
+ / ints 10
(ints 5) + (rev ints 5))
5 rho 6
+ / ^10
^10 / +
reduce (+) ^10
ints 5 + rev (ints 5)
-> 5 $ 6
[6, 6, 6, 6, 6]
op | Monadic | Diadic
⍴ | Returns dimensions | Creates vector or array
a = [1, 2, 3;
4, 5, 6]
-> $a
[3, 2]