Picking Out Elements Using a Logical List

[roadrunner]

Here is a method without a for loop:

Code:


export BOOLLIST3(LA,LB)
BEGIN
 local LC:={};
 local s:=size(LA);
 IF LB(1) THEN LC(0):=LA(1);END; 
 IF s==1 THEN return LC;end;
 LC:=concat(LC,BOOLLIST3(SUB(LA,2,s),CONCAT(SUB(LB,2,SIZE(LB)),LB(1))));
END;

Don't know if it qualifies as simple or not; it runs substantially slower than your version.