<?php

$green  = "31d944";
$red    = "d92929";
$blue   = "1b43d9";
$pink   = "d96ad8";
$orange = "d98225";

$array = compact("green", "red", "blue", "pink", "orange");

var_dump($array);

array(5) {
  ["green"]=>
  string(6) "31d944"
  ["red"]=>
  string(6) "d92929"
  ["blue"]=>
  string(6) "1b43d9"
  ["pink"]=>
  string(6) "d96ad8"
  ["orange"]=>
  string(6) "d98225"
}