[Solved] Extract a specific child from a random structure

[jordi82]

Hello everyone, how exciting, it’s my first post in this community (and can I say that GDevelop and the work you do here are a really cool? There, I said it).

How do I… extract a specific child from a random structure?

I have loaded a series of texts from a JSON into the “Action” variable and I would like to randomly select the “id” (0,1,2,3,4) to display the corresponding text “ph1txt” within a text object (ph1text).
I know for sure that the JSON is properly formatted (if I manually select the specific child, I can display the correct text), but I have searched online and I haven’t found anything specific about it (even from the Quiz Game Template from which I obtained a couple of events, it doesn’t seem to cover this scenario)…

What is the actual result

With these Events, instead of the correct text I have a zero. What am I missing?

[insein]

Hi @jordi82 welcome to the community!

There are few errors in your expressions.

• Change variable RandomID: Random(VariableChildCount(Action.id))
  ^
  Since you used RandomInRange from 1, you dropped out the first child [0]
  Also you added Action twice, so you’re actually getting Action.Action.id

• Change text “ph1text” to: VariableString(Action.id[Variable(RandomlD)].ph1txt)
  ^
  I’m not sure why you used VariableString(actionid)

Note: You should use Variable(RandomID) instead of VariableString(RandomID) since the it’s a number variable and not a string. Also the variable “id” can be an array instead of a structure, I think it would be easier for you to manage.

Hope this helps.

[jordi82]

Hi insein, first of all thank you for your fast reply!

You’re right, there were few errors. I started with GDevelop a week ago and I feel pretty stupid now, I was in confusion, this part about structures and children is pretty complicated, for now.

I inserted all your corrections (Variable(RandomID) and “id” as array too), but I have the same exact problem as before (the 0 instead of the text).

What could be the problem?

As I said, the json file works, infact if I use
Change text “ph1text” to: VariableString(Action.2.ph1txt)
it shows the right text.

[insein]

No problem!

Thanks for sharing screenshot of the JSON, the problem is clear now. The JSON is different than the scene variable you shared, and the expressions I sent are based on the screenshot of the scene variable. That’s why it didn’t work.

This is how the JSON would look like in GDevelop:

Based on the JSON, The “id” is a child of the “Action” array just like the other strings. So the correct expressions would be:

• Change variable RandomID: Random(VariableChildCount(Action))
• Change text “ph1text” to: VariableString(Action[Variable(RandomlD)].ph1txt)

[jordi82]

You’re a lifesaver, insein!

Okay, so I thought I understood JSON, but apparently not…

Now I have RandomID as number, Action as array like in the image and the corrected events, but the random text selection doesn’t work; only the text from the first child always appears (“You prepare to receive a low filtering ball.”).

The first time I knew that something was wrong with the expressione, the second one I had a doubt about the JSon, but now I don’t even know where to look…

Thank you in advance, I’m learning even just looking at your corrections!

[insein]

@jordi82

only the text from the first child always appears

It’s because you’re getting the “ph1txt” string.

So you want to choose a random string from the random child of the Action array?

[jordi82]

I mean that in ph1text appears only the Action[0].ph1txt, but I want to be chosen randomly from
Action[1].ph1txt
Action[2].ph1txt
Action[3].ph1txt
etc

where ph1txt is fixed and [n] is random.
I hope I’m being clear.

[insein]

I tried this in my example and it worked fine for me, it gets a new text every time. I’m not sure why it’s not the case for you.

Note: I forgot to add the -1 to the random expression before, sorry about that (but it’s not related to your current issue)

[jordi82]

Okay, I’m very tired:
in
VariableString(Action[Variable(RandomlD)].ph1txt)
there was a lowercase L instead of a capital I…

Now it’s perfect, thank you again for your time!