
Binary or Logical Selection : Given an array A and a binary or logical vector S, how do I select the rows of A when S = 1 or True ?
Posted:
Sep 22, 2012 4:13 PM


Given a 3 column array A of x,y,z numbers, defining a set of spatial coordinates, and a binary or logical selection vector S (with as many elements as rows in A) :
How do I express the operation of selecting an array R with the set of those coordinates in A where S is 1 (or true) ?
In Apl I write this as R ? S /[1] A .
But a referee of a paper is asking that I express this in standard maths, and I have not yet managed to find an appropriate mathematical expression. Cheers for any help, Beau

