[solved, great solution] json reading - no idea where to start

[Nicole]

After a very productive time with ChatGPT, I tried to work with json.
It talks me into complete nonsense since days. Nothing works.

What I want looks quite easy to me.
Never the less I never did it before.

I grabbed a json file, which looks really nice, if I double-click it and view it in notepad ++
I attach it.

And I have an array TKurse, which "looks the same":

Code: Pascal  [Select][+][-]

1. Type TEineKontraktZeile = packed Record  
2.      Datum: TDateTime;
3.      open, high, low, close, Volume: double;
4.         end;
5. Type TKurse  = array of TEineKontraktzeile;    

So, it shall be easy to take the data from one and fill it in the other?
However it does not work and does not work.

As I worked never before with json, it starts with the basic question, if I have to transform it.
ChatGPT said, I shall make it a string. I did by TstingList and stringList.saveAs made it a file.
So there is the option to work with the json file or the saved stringList of it.
Please hint me!

The next riddle are the meta-data. Sure, we all can read and understand them.
Is there a way that the computer reads them and know, what to do?

What I need is a basic demo, how json works.
ChatGPT made a lot of suggestions for source code and I ended up with compiler warnings "unknown..." something.

So the basic demo shall hint me as well, what to write best into the uses clauses and may be a class or unit to work with best.

thanks

[Nicole]

attach

[cdbc]

Hi
Have you had a look in "C:\...?...\fpcsrc/packages/fcl-json/examples/"
That's where you find the built-in FPC JSON classes and units:

Code: Pascal  [Select][+][-]

1. uses ..., fpjson;

should put the lazarus editor on track, for a start...
Regards Benny

[wp]

There is also a wiki on json: https://wiki.freepascal.org/fcl-json

And the article "Web data formats in Lazarus/FPC" by Michael Van Canneyt contains a chapter on json: https://www.freepascal.org/~michael/articles/webdata/webdata.pdf

[Renat.Su]

I think this article is that you want https://wiki.lazarus.freepascal.org/Streaming_JSON
But it is about class instances not record.

[wp]

Here is a small demo reading your json file and displaying it in a stringgrid and a chart. Note that the analysis of the file is not generally valid here, it is tuned to your data file for simplicity.

[Nicole]

Thank you so very much WP!
This code does all, what I dreamed of!