For_each and conditions


Somewhat new to Terraform.
I am having a hard time understanding how to use the for_each and manipulate the variables from that for_each or even if it’s possble.

Let say I have this variable

variable "my_variable" {
  type = list(object({
    name            = string
    description     = string
    parameters = map(string)

The parameters = map(string) can be diffeent between each object.
For example:

my_variable = [ 
    name          = "name1" 
    description   = "desc1" 
    parameters = {
      "--extra-py-files"    = "extra1"
      "--START_DT"          = "start_dt1"
      "--END_DT"            = "end_dt1"
      "--TempDir"           = "bucket-dir-name1"
    name          = "name2" 
    description   = "desc2" 
    parameters = {
      "--extra-py-files"    = "extra2"

My problem is that I need to do add some prefix to specific parameters if they exist in the parameter = map(string).

For example, if the --TempDir is present, I would need to append the bucket name to it.
var.my_variable[0].parameters["--TempDir"] would become s3://development-bucket-name/bucket-dir-name1

There are 3-4 transformations that I would need to do if specific element are present in the parameters = map(string).

I cannot understand / figure out how to do this.

Any suggestions?

Thanks a lot!