6.6 Array Comprehension
Array comprehension in Haxe uses existing syntax to allow concise initialization of arrays. It is identified by for
or while
constructs:
class Main {
static public function main() {
var a = [for (i in 0...10) i];
trace(a); // [0,1,2,3,4,5,6,7,8,9]
var i = 0;
var b = [while(i < 10) i++];
trace(b); // [0,1,2,3,4,5,6,7,8,9]
}
}
Variable a
is initialized to an array holding the numbers 0 to 9. The compiler generates code which adds the value of each loop iteration to the array, so the following code would be equivalent:
var a = [];
for (i in 0...10) a.push(i);
Variable b
is initialized to an array with the same values, but through a different comprehension style using while
instead of for
. Again, the following code would be equivalent:
var i = 0;
var a = [];
while(i < 10) a.push(i++);
The loop expression can be anything, including conditions and nested loops, so the following works as expected:
class Main {
static public function main() {
var a = [
for (a in 1...11)
for(b in 2...4)
if (a % b == 0)
a+ "/" +b
];
// [2/2,3/3,4/2,6/2,6/3,8/2,9/3,10/2]
trace(a);
}
}