Unfamiliar with APL? You might still be able to follow me in the syntax below. You just have to see
how I use arrays and especially vectors like 4 5 6. 4. This is a vector (list) of three numeric elements
(values). An example of a three-character vector is 'cde'.
Basics
APL in general does not have typed data. Boolean data is not different. It is just like any other
numeric data. It is just found to be Boolean if the values are only 0 or 1. Boolean data usually comes
from comparisons like:
'abcde'∊'be' (belongs to)
0 1 0 0 1
Or
5>3 4 5 6 7 (larger than)
1 1 0 0 0
It can of course be used in Boolean operations
1 0 1∧1 1 0 (and)
1 0 0
1 0 1∨1 1 0 (or)
1 1 1