popCount

popCount(set: long) 🡒 number, pure function

Given a 64-set, returns the total number of elements in that set, i.e. the cardinal, or population count, of that set.

Equivalently, returns the number of bits set to 1 in the binary representation of the provided 64-bit number.

ABC = union(flag(1), union(flag(2), flag(3)))
show scalar "" a1c2 with popCount(ABC) // 3

The value returned by popCount can be between 0 (for the empty set) and 64 (for the complement of the empty set).