handling complex data structure

variables.tf

  [
    {
      id   = "${aws_subnet.publicA.id}"
      cidr = "${aws_subnet.publicA.cidr_block}"
      az   = "${aws_subnet.publicA.availability_zone}"
    },
    {
      id   = "${aws_subnet.publicB.id}"
      cidr = "${aws_subnet.publicB.cidr_block}"
      az   = "${aws_subnet.publicB.availability_zone}"
    },
    {
      id   = "${aws_subnet.publicC.id}"
      cidr = "${aws_subnet.publicC.cidr_block}"
      az   = "${aws_subnet.publicC.availability_zone}"
    },
  ]