how to assign json strings from same dataset to different variables

Question

I have a data set which has a number of devices with similar properties (output). (for example 2 given below). what I do not understand is how do I take each device with the new name and assign it to for example a new div. There can be many devices in dataset. How do I tell my code to whenever there is a new device take out bytes_read and bytes_written and assign them to a new div for example assign

"bdev0": {"Bytes_Read": 0,   "Bytes_Written": 0} to div_one 
"bdev1": {"Bytes_Read": 10, "Bytes_Written": 20  } to div_two

Note that I cannot use something like data.devices[0] because there are many devices and their names keep changing, e.g bdev0, bdev1, bdev2, bde3.. here is the sample of dataset given:

 var data = {
        "devices": [
            {
                "Name": "bdev0",
                "output": {
                    "IO_Operations": 0,
                    "Bytes_Read": 0,
                    "Bytes_Written": 0
                }
            },
            {
                "Name": "bdev1",
                "output": {
                    "IO_Operations": 10,
                    "Bytes_Read": 20,
                    "Bytes_Written": 30
                }
            }
        ]
    }

This is how far I could come but it creates two different strings but how do I assign these separately to two different items. it sounds really stupid but I am really stuck here if for example I want to assign these strings to var a and var b how should I do it

        function myData() {
                for (var i in data.devices){
                       var obj = new Object();
                       obj.Bytes_read = data.devices[i].output.Bytes_Read;
                        obj.Bytes_written  = data.devices[i].output.Bytes_Written;
                         var jsonString= JSON.stringify(obj);
                   console.log(jsonString)
                  }
                }

    myData(data)

Result

 {"Bytes_read":0,"Bytes_written":0}
    {"Bytes_read":20,"Bytes_written":30}

It gives me the data I want but I cannot figure out to assign these sets to var a and var b.

Are you going to receive those datas synchronously or asynchronously? Also, is the amount of data previously known or unknown? — Gui Imamura
– Gui Imamura, Commented Oct 19, 2015 at 14:50
But do you need every data to be processed, or just specific parts of it? i.e., can bdev0 and bdev4 be relevant, but anything else to be irrelevant? — Gui Imamura
– Gui Imamura, Commented Oct 19, 2015 at 14:56
there is nothing else in the data, there are only names of devices e.g bdev0 bdev5 and their outputs so I think I need to process all data — Imo
– Imo, Commented Oct 19, 2015 at 15:03

Nina Scholz · Accepted Answer · 2015-10-19 15:32:36Z

2

If you have the name of the device you can use it as key for the access of the data.

var data = {
        "devices": [{
            "Name": "bdev0",
            "output": {
                "IO_Operations": 0,
                "Bytes_Read": 0,
                "Bytes_Written": 0
            }
        }, {
            "Name": "bdev1",
            "output": {
                "IO_Operations": 10,
                "Bytes_Read": 20,
                "Bytes_Written": 30
            }
        }]
    },
    selectedData = {};

data.devices.forEach(function (a) {
    selectedData[a.Name] = {
        Bytes_Read: a.output.Bytes_Read,
        Bytes_Written: a.output.Bytes_Written
    };
});
document.write('<pre>'+JSON.stringify(selectedData, 0, 4)+'</pre>');

Update: Maybe this is what you want. With the name of the device, the function getDeviceInfo returns the information.

function getDeviceInfo(deviceName) {
    var obj = {};
    data.devices.some(function (a) {
        if (a.Name === deviceName) {
            obj[deviceName] = {
                Bytes_Read: a.output.Bytes_Read,
                Bytes_Written: a.output.Bytes_Written
            };
            return true;
        }
    });
    return obj;
}

var data = {
        "devices": [{
            "Name": "bdev0",
            "output": {
                "IO_Operations": 0,
                "Bytes_Read": 0,
                "Bytes_Written": 0
            }
        }, {
            "Name": "bdev1",
            "output": {
                "IO_Operations": 10,
                "Bytes_Read": 20,
                "Bytes_Written": 30
            }
        }]
    },
    div_one = getDeviceInfo('bdev0'),
    div_two = getDeviceInfo('bdev1');

document.write('<pre>' + JSON.stringify(div_one, 0, 4) + '</pre>');
document.write('<pre>' + JSON.stringify(div_two, 0, 4) + '</pre>');

edited Oct 19, 2015 at 15:32

answered Oct 19, 2015 at 14:25

Nina Scholz

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3 Comments

Imo Over a year ago

yes but what I do not understand is how do I take each device with the new name and assign it to for example a new div. There can be many devices in dataset. How do I tell my code to whenever there is a new device take out bytes_read and bytes_written and assign them to a new div

Nina Scholz Over a year ago

@Imo, from where do you know, what name is important? where do you get the name (like bdev0 or bdev1) from?

Imo Over a year ago

these are coming from a vm and the data is uniform all it has are json objects like the one in the dataset, every property with Name is important

Gui Imamura · Accepted Answer · 2015-10-19 14:15:26Z

0

I'm not quite sure what you're trying to achieve. The code below will take the output property of each element in array and set a to its value when Name is bdev0, and b to it otherwise. I hope this is what you needed:

var a, b;
if (data[0]['Name'] === 'bdev0') {
    a = JSON.stringify(data[0]['output']); // bdev0
    b = JSON.stringify(data[1]['output']); // bdev1
} else {
    a = JSON.stringify(data[1]['output']); // bdev1
    b = JSON.stringify(data[0]['output']); // bdev0
}

answered Oct 19, 2015 at 14:15

Gui Imamura

73112 silver badges34 bronze badges

3 Comments

Imo Over a year ago

Thank you for taking time to answer my question but what I am after is that each time there is a new 'Name' element, eg bdev1, bdev4 I can takeout its bytes_written and bytes_read properties and assign them to another variable. the actual dataset is exactly same as the sample data set but with many other devices

Gui Imamura Over a year ago

If you only need Bytes_Read and Bytes_Written, Nina's code should work for you.

Imo Over a year ago

unfortunately her answer does not answer my question perhaps I am not able to explain myself correctly. I just need a way to assign "bdev0": {"Bytes_Read": 0, "Bytes_Written": 0} to div_one and "bdev1": {"Bytes_Read": 0, "Bytes_Written": 0 } to div_two

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