Learn how to build projects using Terraform.

DevOps for Developers

In this module, you will work from the ground up, starting with what Terraform is and the problems it solves. It will then guide you through the features of Terraform. You will build on your knowledge with the end goal of you being comfortable building projects using Terraform.

Terraform: From Beginner to Master with Examples in AWS

# Set
A set is almost the same as a list. The key difference is that a set only contains unique values.



variable "my_set" {
    type = set(number)
    default = [7, 2, 2]
}

variable "my_list" {
    type = list(string)
    default = ["foo", "bar", "foo"]
}

output "set" {
    value = var.my_set
}

output "list" {
    value = var.my_list
}

output "list_as_set" {
    value = toset(var.my_list)
}


In the above example, we define a variable called `my_set` and initialize it to the set `[7, 2, 2]`. As stated above, a set only contains unique values, 
so when we run this project we will define/specify that the output value set will print `[7, 2]`. Terraform removes one of the `2` values as it was a duplicate. 


To show how sets can be useful, we define a list called `my_list` to repeat the value `foo` twice. The value of the list output will be `["foo", "bar", "foo"]` because we are outputting the value of `my_list`, which is of type list and lists can contain duplicate values. 

For the output `list_as_set`, we are using the `toset` function to convert the `my_list`
variable to a set. The value of this output will be `["foo", "bar"]`. Because we are converting the list to a set, Terraform removes the duplicate value `"foo"`.

Learn how to use the Terraform type constraints Set.

Type Constraints - Set

Set