Best way to delete an item from a JSON string using JsonUtility in Unity 3d

Question

What is the best way to delete an item from a JSON file using Unity 3d's JsonUtility?

I'm assuming you must load it, but: does it need to be parsed or converted to a list?

Once the operation is done, save it. Any help for the middle part would be helpful. Thanks!

score 1 · Accepted Answer · answered Jun 27 '17 at 23:29

1

I'm assuming you must load it, but: does it need to be parsed or converted to a list?

Yes, with JsonUtility you must load it, convert it to List then remove the item from it. First of all, the item must have a variable you can use to identify and remove it. Let's say that the name of the item to delete is "ken";

Test data to load serialize and de-serialize:

[Serializable]
public class PlayerData
{
    public string name;
    public int score;
}

Load(Must be loaded as array then converted back to List):

string jsonToLoad = PlayerPrefs.GetString("Data");
//Load as Array
PlayerData[] _tempLoadListData = JsonHelper.FromJson<PlayerData>(jsonToLoad);
//Convert to List
List<PlayerData> loadListData = _tempLoadListData.OfType<PlayerData>().ToList();

Remove all "ken" Items:

for (int i = 0; i < loadListData.Count; i++)
{
    if (loadListData[i].name == "ken")
    {
        loadListData.Remove(loadListData[i]);
    }
}

or with Linq:

loadListData.RemoveAll((x) => x.name == "ken");

Then you can save it:

string jsonToSave = JsonHelper.ToJson(loadListData.ToArray());
PlayerPrefs.SetString("Data", jsonToSave);
PlayerPrefs.Save();

Of-course, you will need JsonHelper as mentioned in your other post.

answered Jun 27 '17 at 23:29

Programmer

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THANKS Programmer! – Ken Gordon Jun 27 '17 at 23:34
No problem. Remember that you only need to load once, you can then continue to modify the loaded json data until you need to exit then save. – Programmer Jun 27 '17 at 23:35
What if ken were a variable, would I still need the quotes? – Ken Gordon Jun 28 '17 at 16:38
What do you mean by "were a variable"? – Programmer Jun 28 '17 at 16:42
string k="ken"; loadListData.RemoveAll((x) => x.name == k); – Ken Gordon Jun 28 '17 at 16:43
That's what I thought. – Ken Gordon Jun 28 '17 at 16:46
So if k="person: ken", then the line wouldn't work. You'd have to remove the chars before the string you really want with CharsToTrim, right? – Ken Gordon Jun 28 '17 at 16:50
I really don't understand your comment and your question. Can you rephrae with an example? – Programmer Jun 28 '17 at 16:52
I apologize. I'm trying to pass in a variable rather than regular text, so that that item can be deleted from the list. So far it works hard coded, but not when I try to pass in a variable. I'll put the code above... – Ken Gordon Jun 28 '17 at 16:56
Please ask that as a new question because this is a different problem, I will take a look at it. – Programmer Jun 28 '17 at 16:58

Best way to delete an item from a JSON string using JsonUtility in Unity 3d

1 Answers1