find

Find

x?y

The find primitive is used to find the index of an atom y in array x. It returns 0N if the element is not found.

Find is right atomic.

 "XYZ"?"XYXZB"
0 1 0 2 0N
 5 8 5?56 8 1 5
0N 1 0N 0

For dictionaries, returns the keys associated with the given values:

 (`a`b`c`d!23 14 9 5)?9 14
`c`b

K3

In K3, Find is non-atomic. It considers y as a single unit, and will return a single index for it. ?/: is needed to simulate the functionality of later Ks.