How to make a dictionary of dictionaries in JSON?

Question

Right now I have this structure in JSON

"Types":[  
            {  
               "LowCadence":[  
                  {  
                     "Reinforcement":"-1",
                     "Weight":"100",
                     "Message":"Pay attention. You're running low cadence. Your cadence is %d steps per minute."
                  }
               ]
            },
            {  
               "NormalCadence":[  
                  {  
                     "Reinforcement":"0",
                     "Weight":"100",
                     "Message":"Great, your cadence is on target. Cadence is %d steps per minute.",
                     "EnforcementSound":"ding"
                  }
               ]
            },
            {  
               "HighCadence":[  
                  {  
                     "Reinforcement":"1",
                     "Weight":"100",
                     "Message":"Slow down. You're running over your planned cadence. Cadence is %d steps per minute."
                  }
               ]
            }
         ]

But I would like it to have this structure

enter image description here

Does anyone know how to write it in JSON?

In JSON, the "correct" name for this thing seems to be "object", not "dictionary". https://tools.ietf.org/html/rfc8259#section-4 — Jonny, Nov 30 '18 at 03:40

score 3 · Accepted Answer · edited May 23 '17 at 11:44

I believe your JSON would look something like:

var Types = {
    NormalHR: {
        Reinforcement: 0,
        Weight: 100,
        Message: 'Great! Your heart rate is in the zone.',
        EnforcementSound: 'ding'
    },
    HighHR: {
        Reinforcement: 1,
        Weight: 100,
        Message: 'Slow down. Your heart rate is too high!'
    },
    LowHR: {
        Reinforcement: -1,
        Weight: 100,
        Message: 'Speed up. Low heart rate.'
    }
};

As @Balder says in their answer, you can then access use dictionary-style syntax, like:

Types['NormalHR']['Reinforcement']

You could also use property-accessor syntax, like:

Types.NormalHR.Reinforcement

The reason I didn't include the "type" of each item, is that you can easily infer it for building your grid - as follows:

typeof Types.NormalHR.Reinforcement (this will return "number")
typeof Types.NormalHR.Message (this will return "string")

Similarly, to get the counts - you can count the properties of a specific object. In modern browsers, try:

Object.keys(Types.NormalHR).length (this will return 2)

For older browsers, refer to other methods here: How to efficiently count the number of keys/properties of an object in JavaScript?

Hope this helps!

Thank you for you answer Troy, this is not for web, it's for iOS app — Eugene Gordin, Jun 18 '15 at 21:52

score 2 · Answer 2 · answered Jun 18 '15 at 22:09

2

In objective C you can write:

NSDictonary *types = @{
@"NormalHR": @{
    @"Reinforcement": [NSNumber numberWithInt:0],
    @"Weight": [NSNumber numberWithInt:100],
    @"Message": @"Great! Your heart rate is in the zone.",
    @"EnforcementSound": @"ding"
},
@"HighHR": @{
    @"Reinforcement": [NSNumber numberWithInt:1],
    @"Weight": [NSNumber numberWithInt:100],
    @"Message": @"Slow down. Your heart rate is too high!"
},
@"LowHR": @{
    @"Reinforcement": [NSNumber numberWithInt:-1],
    @"Weight": [NSNumber numberWithInt:100],
    @"Message": @"Speed up. Low heart rate."
}

};

answered Jun 18 '15 at 22:09

simone

105
9

I need a JSON...so can pass it cross-platform – Eugene Gordin Jun 18 '15 at 22:52
1

So the correct structure of needed json is the Troy Alford's one. If you need to serialize it into a NSDictonary take a look here: http://stackoverflow.com/a/10121757/1306216 – simone Jun 19 '15 at 06:47

score 0 · Answer 3 · answered Jun 18 '15 at 21:25

0

You dont have "dictionaries" in json, but you have key/value arrays which works pretty much like them.

In your code if you want to access:

Normal Cadence > Message you only must do:

Types["NormalCadence"]["Message"]

Is similar to a .Net Dictionary, but is not exactly a Dictionary

answered Jun 18 '15 at 21:25

Manjar

2,849
27
39

I don't believe this will work, as you're using a property-style accessor to try and get a value out of an array. – Troy Alford Jun 18 '15 at 21:31
Yes, because after json is proccess it becames an array in javascript – Manjar Jun 18 '15 at 21:32
which language is that? Is it Swift? I'm using Objective-c...in the array JSON case, I have to parse this into a dictionary before I can use it, which is an overhead over the plist way..so I was curious if it's possible to mimic the same with JSON by formatting – Eugene Gordin Jun 18 '15 at 21:33
Ahh - my answer may or may not help, then. Perhaps I misunderstood. Languages which serialize into / out of JSON handle dictionaries in their own way. I'm most familiar with .NET's serialization - which is based on how you declare the object serializer itself - and essentially just uses objects. – Troy Alford Jun 18 '15 at 21:47

How to make a dictionary of dictionaries in JSON?

3 Answers3