How do I convert a string to a list

I have a resource that returns an ID during apply. I have a second resource that needs to consume that ID for one of its attributes but it needs a list of strings. What would be the best method of accomplishing this? This is all within a single .tf file. Specifically I’m looking at backend_address_pool_ids.

resource "azurerm_lb_backend_address_pool" "ilb-backend" {
  loadbalancer_id     =
  name                = "BackEndPool"

resource "azurerm_lb_probe" "ilb-probe" {
  loadbalancer_id     =
  name                = "lbprobe"
  port                = 8008

resource "azurerm_lb_rule" "lb-haports-rule" {
  loadbalancer_id                     =
  name                                = "rule-haports-rule"
  protocol                            = "All"
  frontend_port                       = 0
  backend_port                        = 0
  frontend_ip_configuration_name      = "ilb-pip-edge-eastus"
  probe_id                            =
  backend_address_pool_ids            =

You have a single item of data and want to convert it to a list containing that single item? Just put some square brackets around it then…

Perfect, thank you. I knew it had to be something simple but I was having trouble finding it.