Create a map from a list of of a key in a element

user_2858926 0
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I'm trying to convert a list of items into a map. The element contains a key named tags that contains multiple tags separated by ','

The key should match all nodes that contains the tag.

variable "list" {
  type = list(map(string))
  default = [
    { a : "a", tags : "k1" },
    { a : "b", tags : "k1" },
    { a : "c", tags : "k1,k2" },
    { a : "d", tags : "k2" },
    { a : "e", tags : "k2" }
  ]
}
    
// Output wanted
// {
//  "k1" : [{a: a}, {a: b}, {a: c}],
//  "k2" : [{a: d}, {a: e}, {a: c}]
// }

I've tried:

[for n in var.list: {for t in split(",", n["tags"]): t => n}]

[
  {
    "k1" = {a: a}
  },
  {
    "k1" = {a: b}
  },
  {
    "k1" = {a: c},
    "k2" = {a: c}
  },
  {
    "k2" = {a: d}
  },
  {
    "k2" = {a: e}
  },
]

But I don't know how to merge it after that.

terraform
1 Answers

This is a bit trickier. I used two helper data types, helper_list and helper_map. The first one check what keys are there, k1, k2. The second creates a list with individual values. The final_map converts helper_map into desired map:

locals {

  helper_list = distinct(flatten(
        [for n in var.list: [for t in split(",", n["tags"]): t]]))
        
  helper_map = flatten([
             for k in local.helper_list:
             [
               for item in var.list: 
               {"${k}" = {a = item["a"]}} if length(regexall(k, item["tags"])) > 0
             ]
           ])
        
  final_map = {for item in local.helper_map: keys(item)[0] => values(item)[0]...}
}


output "test1" {
   value = local.final_map
}

Outcome:

est1 = {
  "k1" = [
    {
      "a" = "a"
    },
    {
      "a" = "b"
    },
    {
      "a" = "c"
    },
  ]
  "k2" = [
    {
      "a" = "c"
    },
    {
      "a" = "d"
    },
    {
      "a" = "e"
    },
  ]
}
user_2488230
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