Terraform supports conditional expressions that can be used to assign variable values based on conditions.

variable "environment" {
  description = "Deployment environment"
  type        = string
}
 
resource "aws_instance" "example" {
  ami           = "ami-0c55b159cbfafe1f0"
  instance_type = var.environment == "production" ? "t2.large" : "t2.micro"
}