## Dyadic functions with Rank

The result of Membership (`∊`

) says, for each element of the left argument, whether it appears in the right argument.

'rank' ∊ 'array'
1 1 0 0
'rank' ∊ ↑'array' 'shape' 'bound'
1 1 1 0

Using Rank we can ask about membership in multiple arrays separately.

'rank' ∊⍤1 ↑'array' 'shape' 'bound'
1 1 0 0
0 1 0 0
0 0 1 0