Re: Create NTTable from JSON

["Veseli, Sinisa via Core-talk" <core-talk at aps.anl.gov>]

Hi,

I am not sure if this helps, but if the object has correct structure as far as number/type columns, at the moment you could do something like this:

>>> nt = NtTable([STRING, INT, DOUBLE])

>>> nt.setColumn(0, ['xx', 'yy', 'zz'])

>>> nt.setColumn(1, [1, 2, 3])

>>> nt.setColumn(2, [11.1, 22.2, 33.3])

>>> nt.useNumPyArrays=False

>>> myString = json.dumps(dict(nt))

>>> print(myString)

{"labels": [], "value": {"column0": ["xx", "yy", "zz"], "column1": [1, 2, 3], "column2": [11.1, 22.2, 33.3]}, "descriptor": "", "timeStamp": {"secondsPastEpoch": 0, "nanoseconds": 0, "userTag": 0}, "alarm": {"severity": 0, "status": 0, "message": ""}}

>>> nt2 = NtTable([STRING, INT, DOUBLE])

>>> nt2.set(json.loads(myString))

>>> print(nt2)

epics:nt/NTTable:1.0

    string[] labels []

    structure value

        string[] column0 [xx, yy, zz]

        int[] column1 [1,2,3]

        double[] column2 [11.1,22.2,33.3]

    string descriptor

    time_t timeStamp

        long secondsPastEpoch 0

        int nanoseconds 0

        int userTag 0

    alarm_t alarm

        int severity 0

        int status 0

        string message

>>>

Sinisa

--

Siniša Veseli

Scientific Software Engineering & Data Management

Advanced Photon Source

Argonne National Laboratory

sveseli at anl.gov

(630)252-9182

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From: Core-talk <core-talk-bounces at aps.anl.gov> on behalf of Karl Vestin via Core-talk <core-talk at aps.anl.gov>
Sent: Wednesday, April 5, 2023 8:25 AM
To: core-talk at aps.anl.gov <core-talk at aps.anl.gov>
Subject: Create NTTable from JSON

 

Dear all,

 

Are there any functions available to generate a NTTable from a JSON object or JSON schema? I have found a function to generate JSON from a PVObject, but not the other way around.

 

Anyone have insights to share?

 

Karl Vestin

Group Leader Hardware and Integration

Integrated Control Systems Division

European Spallation Source ERIC

 

+46721792066

P.O Box 176, SE 221 00 Lund, Sweden

Visiting address: Odarslövsvägen 113, Lund