如何将项添加到关联数组？

let associativeArray = {};
associativeArray["key"] = "value";

associative_array = {}
associative_array["key"] = "value"

$associativeArray = array();
$associativeArray["key"] = "value";

import java.util.HashMap;

HashMap<String, String> associativeArray = new HashMap<String, String>();
associativeArray.put("key", "value");

using System.Collections.Generic;

Dictionary<string, string> associativeArray = new Dictionary<string, string>();
associativeArray.Add("key", "value");