[Simple] How to retrieve the Hashtable value, stored in a list?

Question

Hello, guys! Could you please help me with retrieving the value of a key, contained in a list? Here is the script:

     public Hashtable all_containers_hashtable = new Hashtable();
 
     public List<string> container_list_1 = new List<string>();
     public List<string> container_list_2 = new List<string>();
 
 
     // Start is called before the first frame update
     void Start()
     {
         container_list_1.Add("name_1");
         container_list_1.Add("description_1");
         container_list_1.Add("param_1_1");
         container_list_1.Add("param_1_2");
         container_list_1.Add("param_1_3");
         all_containers_hashtable.Add("card_1", container_list_1);
 
         container_list_2.Add("name_2");
         container_list_2.Add("description_2");
         container_list_2.Add("param_2_1");
         container_list_2.Add("param_2_2");
         container_list_2.Add("param_2_3");
         all_containers_hashtable.Add("card_2", container_list_2);
 
 
     }
 
     // Update is called once per frame
     void Update()
     {
 
         if (Input.GetKeyDown(KeyCode.Q)) {
             Debug.Log(all_containers_hashtable["container_list_1"]);
 //returns the type: List
             Debug.Log(all_containers_hashtable["container_list_1"][1]); 
 // D o e s n ' t w o r k (intended, it will return "description_1"), instead it gives error
         }
 
 
     }

Answer 1

Best Answer

Answer by Dragate · Jul 20, 2019 at 03:24 PM

The hashtable doesn't have a "container_list_1" key. That is a value corresponding to the "card_1" key. Also, since hashtables can receive values of all types without pre-defining (in contrast to dictionaries), you need to typecast your value to access its elements.

 List<string> list = (List<string>) all_containers_hashtable ["card_1"]; // Get list by typecasting
 Debug.Log(list[1]); // Access the 2nd element of the list

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Fewpwew130 · Jul 20, 2019 at 07:50 PM 0

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Thank you! It works! P.S. That solution requires the declaration (typecasting) of another variable - i.e. "list". Which increases the variable count in the script. Is there a way to get the element without that - another variable?

Dragate Fewpwew130 · Jul 20, 2019 at 08:05 PM 1

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It's just a local declaration. In one line it would be:

 Debug.Log(((List<string>) all_containers_hashtable ["card_1"])[1]);

It still would unbox the whole list temporarily to get hold of the element you want to access.

Fewpwew130 Dragate · Jul 20, 2019 at 08:19 PM 0

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Thank you! This is what I was looking for.

[Simple] How to retrieve the Hashtable value, stored in a list?

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