# PrimitiveArrayFunctions2(A, B)¶

map(f, a) applies function f to each member of primitive array a resulting in a new primitive array over a possibly different underlying domain.
reduce(f, a, r) applies function f to each successive element of the primitive array a and an accumulant initialized to r. For example, reduce(_+\\$Integer, [1, 2, 3], 0) does 3+(2+(1+0)). Note: third argument r may be regarded as the identity element for the function f.
scan(f, a, r) successively applies reduce(f, x, r) to more and more leading sub-arrays x of primitive array a. More precisely, if a is [a1, a2, ...], then scan(f, a, r) returns [reduce(f, [a1], r), reduce(f, [a1, a2], r), ...].