Struggling with decoding this JSON

Hi,
I am working on my first plugin, and I have hit the end of my knowledge. I get the following json back, by doing

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status=requests.get(url)
alljson = json.loads(status.text)


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{u'info': {u'opt': 119, u'core': u'2_5_2', u'leds': {u'count': 151, u'rgbw': False, u'maxpwr': 850, u'pwr': 847, u'pin': [2], u'maxseg': 10}, u'udpport': 21324, u'ver': u'0.8.6', u'name': u'WLED', u'vid': 1910255, u'brand': u'WLED', u'palcount': 50, u'uptime': 164461, u'product': u'DIY light', u'live': False, u'btype': u'bin', u'fxcount': 83, u'freeheap': 20480, u'mac': u'2cf432779560', u'arch': u'esp8266'}, u'state': {u'on': True, u'nl': {u'on': False, u'dur': 60, u'tbri': 0, u'fade': True}, u'ps': -1, u'udpn': {u'recv': True, u'send': False}, u'transition': 650, u'seg': [{u'ix': 128, u'cln': -1, u'sx': 170, u'fx': 54, u'rev': False, u'stop': 151, u'len': 151, u'col': [[11, 22, 33], [0, 51, 255], [0, 0, 0]], u'start': 0, u'sel': True, u'pal': 8, u'id': 0}], u'bri': 255, u'pl': -1}, u'palettes': [u'Default', u'Random Cycle', u'Primary Color', u'Based on Primary', u'Set Colors', u'Based on Set', u'Party', u'Cloud', u'Lava', u'Ocean', u'Forest', u'Rainbow', u'Rainbow Bands', u'Sunset', u'Rivendell', u'Breeze', u'Red & Blue', u'Yellowout', u'Analogous', u'Splash', u'Pastel', u'Sunset 2', u'Beech', u'Vintage', u'Departure', u'Landscape', u'Beach', u'Sherbet', u'Hult', u'Hult 64', u'Drywet', u'Jul', u'Grintage', u'Rewhi', u'Tertiary', u'Fire', u'Icefire', u'Cyane', u'Light Pink', u'Autumn', u'Magenta', u'Magred', u'Yelmag', u'Yelblu', u'Orange & Teal', u'Tiamat', u'April Night', u'Orangery', u'C9', u'Sakura'], u'effects': [u'Solid', u'Blink', u'Breathe', u'Wipe', u'Wipe Random', u'Random Colors', u'Sweep', u'Dynamic', u'Colorloop', u'Rainbow', u'Scan', u'Dual Scan', u'Fade', u'Chase', u'Chase Rainbow', u'Running', u'Saw', u'Twinkle', u'Dissolve', u'Dissolve Rnd', u'Sparkle', u'Dark Sparkle', u'Sparkle+', u'Strobe', u'Strobe Rainbow', u'Mega Strobe', u'Blink Rainbow', u'Android', u'Chase', u'Chase Random', u'Chase Rainbow', u'Chase Flash', u'Chase Flash Rnd', u'Rainbow Runner', u'Colorful', u'Traffic Light', u'Sweep Random', u'Running 2', u'Red & Blue', u'Stream', u'Scanner', u'Lighthouse', u'Fireworks', u'Rain', u'Merry Christmas', u'Fire Flicker', u'Gradient', u'Loading', u'In Out', u'In In', u'Out Out', u'Out In', u'Circus', u'Halloween', u'Tri Chase', u'Tri Wipe', u'Tri Fade', u'Lightning', u'ICU', u'Multi Comet', u'Dual Scanner', u'Stream 2', u'Oscillate', u'Pride 2015', u'Juggle', u'Palette', u'Fire 2012', u'Colorwaves', u'BPM', u'Fill Noise', u'Noise 1', u'Noise 2', u'Noise 3', u'Noise 4', u'Colortwinkles', u'Lake', u'Meteor', u'Smooth Meteor', u'Railway', u'Ripple', u'Twinklefox', u'Twinklecat', u'Halloween Eyes']}


I then can extract just the status by

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statusjson = alljson.get("state")


Which returns

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{u'on': True, u'nl': {u'on': False, u'dur': 60, u'tbri': 0, u'fade': True}, u'ps': -1, u'udpn': {u'recv': True, u'send': False}, u'transition': 650, u'seg': [{u'ix': 128, u'cln': -1, u'sx': 170, u'fx': 54, u'rev': False, u'stop': 151, u'len': 151, u'col': [[11, 22, 33], [0, 51, 255], [0, 0, 0]], u'start': 0, u'sel': True, u'pal': 8, u'id': 0}], u'bri': 255, u'pl': -1}


I have had no problem extracting the states I need with statusjson["transition"] for example. I am struggling to then get the elements I need from the "seg" portion as when I try to get just that with

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segjson = statusjson.get("seg")

I get the following

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[{u'ix': 128, u'cln': -1, u'sx': 170, u'fx': 54, u'rev': False, u'stop': 151, u'len': 151, u'col': [[11, 22, 33], [0, 51, 255], [0, 0, 0]], u'start': 0, u'sel': True, u'pal': 8, u'id': 0}]


Which I can no longer extract individual elements, and I am out of my depth. I am especially interested in the "col" values, but also the "pal" but I don't seem to be able to reference those elements at all.

Any pointers ?

What you're dealing with are dicts and lists. You don't need to use the 'get' part--usually that's only used if you don't know if a key exists. For example,

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x = dict.get('foo', 123)

Dict elements are located by using their keys. List elements are found by using their indexes (as they are with tuples).

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x = {'a': 1, 'b': 2, 'c': 3}
y = [1, 2, 3]

print(x['a'])

print(y[0])

Here are some examples that will hopefully set you on the course:

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print(j['info'])

print(j['info']['opt'])

print(j['state'])

print(j['state']['seg'])

for thing in j['state']['seg']:
    print(thing)
    print(thing['fx'])
   
print(j['state']['seg'][0]['fx'])

Dicts and lists are hugely useful. There are tons of tutorials online that explain how to use them.

[jay (support)]

Not positive what you're needing, but statusjson is a dictionary. 'state' is a dictionary inside the statusjson dictionary. To get the 'on' value of the 'state' dictionary, you'd get it like this:

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statusjson['state']['on']

That would return the boolean True.

Likewise, if you wanted to get the 'pal' value in the 'seg' dictionary in the 'state' dictionary:

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statusjson['state']['seg']['pal']

that would return the numeric value 8.

The 'col' value inside 'seg' inside 'state' is a list of 3 lists. So:

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col_list = statusjson['state']['seg']['col']

returns the following list:

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[[11, 22, 33], [0, 51, 255], [0, 0, 0]]

To get the first list ([11, 22, 33]):

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first_col_list = col_list[0]

(python lists are 0 indexed, so the first item is 0, second item is 1, etc).

To the 33:

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third_value_of_first_col_list = first_col_list[2]

[EDIT] looks like Dave and I were answering at the same time. Basically, you should read up on Python Dictionaries and Lists, which will make this much clearer.

[EDIT] looks like Dave and I were answering at the same time. Basically, you should read up on Python Dictionaries and Lists, which will make this much clearer.

Jinx. Buy me a Coke.

Thanks both, much appreciated and I will try and build my base knowledge up. I tend to learn by trying, but realise no substitute for a bit of structure in the foundation. Having something to try really helps, and I had hit a bit of a brick wall.

No worries whatsoever--we were all there once. Nobody gets there alone.

So something a little strange is going on. I think I have my head around most of this now, and have this working, apart for things in the "seg", which appears to be a list with one value.
when I try

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statusjson['state']['seg']['pal']

I get the following error (all of the other references are fine and worked as I thought they should)

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TypeError: list indices must be integers, not str

and I get the same if I try

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col_list = statusjson['state']['seg']['col']

And it looks to me like "seg" is a list with a single item containing

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{u'ix': 128, u'cln': -1, u'sx': 170, u'fx': 54, u'rev': False, u'stop': 151, u'len': 151, u'col': [[11, 22, 33], [0, 51, 255], [0, 0, 0]], u'start': 0, u'sel': True, u'pal': 8, u'id': 0}


As this is what is returned when I try the following

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col_list = statusjson['state']['seg'][0]

I will keep working from the bottom up to see as this is almost certainly me missing something !

You're getting there. The error is a hint that you're hitting on a list with a dictionary key.

Try this:

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col_list = statusjson['state']['seg'][0]['col']


It looks like that reference will return a list of lists.

That was it, the levels of nesting was making my head explode. Thanks so much for taking the time, I thought I was getting in the abstract and with simply examples but when the rubber hit the road!

This community is truly enriched by what you do, and I appreciate it, and also for the dedication of Jay and Matt.

Neil

No worries. Once you come to grips with the way that dictionaries, lists and tuples work, you'll find that they're used all over the place (because they are super useful). Be sure to check out some tutorials on these types of data structures because there are a few tricks and traps along the way that you might not expect. Take 'slicing' for instance--you can take a slice of a list (or a tuple) with this structure:

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x = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]

print(x[0:4])

which yields '1, 2, 3, 4'. The slice goes through to index 3--the second slice index goes "through but not including"--so 0 to 4 gives you the 0, 1, 2, 3 indexes. Like I said, maybe not what you'd expect, but it makes sense once you know about it. There are other funny bits too. For example:

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print(x[-1])

Happy to help. I got a lot of lifts from folks here as I was getting started.

Cheers.

[jay (support)]

Yep - dictionaries and lists are critical parts of Python - you can't do much without understanding those. I highly recommend completing an intro Python tutorial - it won't take long (a couple of hours probably) and they usually have good examples as you go. Building a solid baseline understanding will keep you out of trouble in the future and will make it much easier to dive into the Python docs when you need something further.

and will make it much easier to dive into the Python docs when you need something further.

I’m glad I’m not the only one that still has to!


Sent from my iPhone using Tapatalk Pro

[jay (support)]

and will make it much easier to dive into the Python docs when you need something further.

I’m glad I’m not the only one that still has to!

I don't think anyone (except possibly the actual contributors to Python) know everything off the top of their heads. Reference docs are there for a reason!

Just a little follow up - I did as Jay suggested and completed the Microsoft online course which took a few hours but was well worth the effort. I am a good way into plugin number 2, which may end up being for an audience of me but I still wanted to do it. I have been able to be way more effective with the base learning and support without having to call for help (so far). Still some schoolboy errors from me, but I am much better at figuring out why it isn’t working. I did get in a hole around plugin props vs prefs but figured it out by picking through the docs and other plugins.

It is quite rewarding figuring this stuff out and when faced with a use case being able to design a workable plugin. My second one will be much cleaner and more elegant thanks to the help and pointers.

Neil

I think a lot of plugins started out as solutions to the authors' problems and grew from there.

Personally, I'm still consistently learning new and better ways of doing things. For me, that's half the fun.