TheBackShed.com

Forum Index : Microcontroller and PC projects : Json$ parsing help

Author

Message

Doktorn

Newbie

Joined: 09/07/2019
Location: Sweden
Posts: 17

Posted: 02:35pm 02 Nov 2025

Copy link to clipboard

Print this post

Hi

I have a Json$ file with multiple instances of a label ”SEK_per_kWh”.
On another system I can use print Json$(x$,”SEK_per_kWh[6]”) for
instance nbr 6. I have tried with Print Json$(inp%(),”SEK_per_kWh”)
witch correctly give me the first post but Print Json$(inp%(),”SEK_per_kWh[6]”)
gives nothing.

Can’t get it to work in MM RP2040 V6.00.01.RC6.

My question, how can I parse a Json file with multiple instances of
the same label.

/Lasse

N/A

lizby
Guru

Joined: 17/05/2016
Location: United States
Posts: 3451

Posted: 02:43pm 02 Nov 2025

Copy link to clipboard

Print this post

Post your entire json string.

PicoMite, Armmite F4, SensorKits, MMBasic Hardware, Games, etc. on fruitoftheshed

Doktorn

Newbie

Joined: 09/07/2019
Location: Sweden
Posts: 17

Posted: 02:50pm 02 Nov 2025

Copy link to clipboard

Print this post

Hi

The file is large, 13620 bytes.

It's this times 96

{"SEK_per_kWh":0.27497,"EUR_per_kWh":0.02498,"EXR":11.007546,"time_start":"2025-11-02T00:00:00+01:00","time_end":"2025-11-02T00:15:00+01:00"}

/Lasse

N/A

Pluto
Guru

Joined: 09/06/2017
Location: Finland
Posts: 387

Posted: 03:43pm 02 Nov 2025

Copy link to clipboard

Print this post

Hi Lasse,
It seems that we are working with very similar topics! You are parsing swedish and myself finnish electricity prices.

Starting from the long Json$ string (stoted in a longsting buffer) I first search for the first "{" and remove everything up to that point. Then search for the keywords in the Json$. Save data in arrays.
Then again remove the "used" part of the Json$ (LONGSTRING TRIM buff%(),1) and the starting over again.

Here is short part of my code:

WEB open TCP CLIENT url$,80
WEB TCP CLIENT REQUEST Query$,buff%(),15000
WEB close TCP CLIENT
print "TCP time:",timer,"ms"
'a%: position of first "{" in buff%().
print "LLEN(buff%() Part 1:";LLEN(buff%())
a%=LinStr(buff%(),"{")-1: if deb then print "a%=";a%

If a% <> -1 Then
'LongString trim buff%(),a% 'tar bort a% tecken fr?n b?rjan av buff%()
if deb then Print "buff%()=",
if deb then LongString print buff%()

for i=1 to 48

a%=LinStr(buff%(),"{")-1 'find position of first {
LongString trim buff%(),a% 'remove all before {

PriceQuart(i)=CINT(val(Json$(buff%(),"hinta"))*1.255*100)/100 'incl 25.5% VAT
ClockQuart$(i)=right$(Json$(buff%(),"aikaleima_suomi"),5)

a%=a%+1
LongString trim buff%(),1 'remove first char left in buff().(should be "{")

next i

For some unknown reason I was not able to get all 96 datapoints reliably received at once; hence i=1 to 48. (And later a similar sequence for i=49 to 96)

Short dictionary:
hinta: price
aikaleima_suomi: timelabel_finland

My code is based on what others have published on thebackshed. You will probably find better explanations by others in this forum.

Lycka till!

Pluto

Doktorn

Newbie

Joined: 09/07/2019
Location: Sweden
Posts: 17

Posted: 08:32pm 02 Nov 2025

Copy link to clipboard

Print this post

lizby

This is the entire json string.

/Lasse

N/A

Doktorn

Newbie

Joined: 09/07/2019
Location: Sweden
Posts: 17

Posted: 09:08pm 02 Nov 2025

Copy link to clipboard

Print this post

Hi Pluto

Thanks for the tip about parsing my Json$ file. I have used a similar technique when I
decoded XML price documents from the entsoe price database a couple of years ago.
I have an application on an ESP32 with Annex RDS that works well where you can use Json$
in the following way pris$(1)=json$(le$,"SEK_per_kWh[1]”),pris$(2)=json$(le$,"SEK_per_kWh[2]”)
etc. What I was looking for was from the manual's description of the JSON$ parser.

From the manual.
JSON$(a%(), “weather[0].description”) What does the number within [0] mean?

/Lasse

N/A

Print this page

To reply to this topic, you need to log in.