Pivoting a JavaScript array

Question

I have source data which follows the following format where I have a collection of values per category

var data = [
{'name': 'Test 1',
'values': {
'50':0,
'51':10,
'52':0,
'53':10,
'54':60,
'55':999
}},
{'name': 'Test 2',
'values': {
'50':33,
'51':3,
'52':333,
'53':3,
'54':3,
'55':3333
}},
{'name': 'Test 3',
'values': {
'50':55,
'51':66,
'52':77,
'53':88,
'54':99,
'55':100
}}];

I need to pivot this to create an array for each value individually. So my result set would be

var result = [
{'value':50, 'Test 1':0, 'Test 2':33, 'Test 3': 55},
{'value':51, 'Test 1':10, 'Test 2':3, 'Test 3': 66},
{'value':52, 'Test 1':0, 'Test 2':333, 'Test 3': 77},
{'value':53, 'Test 1':10, 'Test 2':3, 'Test 3': 88},
{'value':54, 'Test 1':60, 'Test 2':3, 'Test 3': 99},
{'value':55, 'Test 1':999, 'Test 2':3333, 'Test 3': 100}
]

I cannot see how to create new new array by looping through the data array

would be easier to "see" if you formatted your data.

I wrestled a bear once.
– I wrestled a bear once.

2019-09-10 12:45:54 +00:00
Commented Sep 10, 2019 at 12:45 — I wrestled a bear once.
– I wrestled a bear once., Commented Sep 10, 2019 at 12:45
Can Ia sk how I do that?

Mike
– Mike

2019-09-10 12:47:33 +00:00
Commented Sep 10, 2019 at 12:47 — Mike
– Mike, Commented Sep 10, 2019 at 12:47

Nina Scholz · Accepted Answer · 2019-09-10 13:03:05Z

2

You could take an object for collecting same keys and get the values from the object as result set.

var data = [{ name: 'Test 1', values: { 50: 0, 51: 10, 52: 0, 53: 10, 54: 60, 55: 999 } }, { name: 'Test 2', values: { 50: 33, 51: 3, 52: 333, 53: 3, 54: 3, 55: 3333 } }, { name: 'Test 3', values: { 50: 55, 51: 66, 52: 77, 53: 88, 54: 99, 55: 100 } }]
    result = Object.values(data.reduce((r, { name, values }) => {
        Object.entries(values).forEach(([k, v]) => {
            r[k] = r[k] || { value: +k };
            r[k][name] = v;
        });
        return r;
    }, {}));

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Sep 10, 2019 at 13:03

Nina Scholz

388k26 gold badges367 silver badges417 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

SpaceBrain · Accepted Answer · 2019-09-10 13:36:39Z

There may be more efficient ways to do this but this is very fault tolerant in case your data is not so clean.

var data = [
{'name': 'Test 1',
'values': {
'50':0,
'51':10,
'52':0,
'53':10,
'54':60,
'55':999
}},
{'name': 'Test 2',
'values': {
'50':33,
'51':3,
'52':333,
'53':3,
'54':3,
'55':3333
}},
{'name': 'Test 3',
'values': {
'50':55,
'51':66,
'52':77,
'53':88,
'54':99,
'55':100
}}];

var piv_data = [];

for(var i = 0; i < data.length; i++)
{
    var name = data[i].name;
    for(var value in data[i].values)
    {
        var index = -1;
        for(var x=0; x < piv_data.length; x++)
        {
            if(piv_data[x].value == value)
            {
                index = x;
                break; 
            }
        }
        if(index == -1)
        {
            piv_data.push({ 'value': value })
            index = piv_data.length -1;
        }
        piv_data[index][name] = data[i].values[value]
    }
}

console.log(piv_data)

Collectives™ on Stack Overflow

Pivoting a JavaScript array

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related