Calculating length of array within an object within an array

Question

I'm having trouble creating a loop that is referencing an array within an object within an array.

   var data_dictionary = [{
    "category": "Food",
    "items": [
        {
            "object": "Apple",
            "price": 2.21

        },
        {
            "object": "Banana",
            "price": 1.12
        }
     ]
  }, {
   "category":  "Goods",
   "items":  [
        {
            "object":  "Lawnmower",
            "price":   25.55
        },
        {
            "object":  "Bicycle",
            "price":   12.21
        }
     ]
  }
]

I would like to run a loop that will return the # of "objects", but I'm running into problems

var result =[] 
var temp = []
  for (var i=0; i < data_dictionary.length; i++) {
        for (var c=0; c < data_dictionary[i].items.length; c++) {
          temp.push (data_dictionary[i].items[c].object)
        }
      }
      result.push (temp.length)

The issue has to do with calculating the length in "c < data_dictionary[i].items.length", and likely in the following line as well.

Ideally, I would like result to be 4, since there are 4 objects.

Thanks for reading.

please add the wanted result. is it a number or an array with the objects with object inside? — Nina Scholz
– Nina Scholz, Commented May 25, 2016 at 9:18
Now your data_dictionary is the array with only one element. Is this a typo or a mistake? — MysterX
– MysterX, Commented May 25, 2016 at 9:20
your input data_dictionary is not a properly formed array ... Please check that .. Couple of brackets are missing ... — seekers01
– seekers01, Commented May 25, 2016 at 9:20
Your data_dictionary is not well formated in the first place. You're defining category and items twice inside the same object. — Craveiro
– Craveiro, Commented May 25, 2016 at 9:21
Your json object is wrong one json object cannot contain duplicate keys. in your case you are dulicating "category" and "items" multiple time. — Sandeeproop
– Sandeeproop, Commented May 25, 2016 at 9:22

Parag Bhayani · Accepted Answer · 2016-05-25 09:28:27Z

1

your data and code should be

var data_dictionary = [{
    "category": "Food",
    "items": [
        {
            "object": "Apple",
            "price": 2.21

        },
        {
            "object": "Banana",
            "price": 1.12
        }
     ]
  }, {
   "category":  "Goods",
   "items":  [
        {
            "object":  "Lawnmower",
            "price":   25.55
        },
        {
            "object":  "Bicycle",
            "price":   12.21
        }
     ]
  }
]

var result;
var temp = [];
for (var i=0; i < data_dictionary.length; i++) {
    for (var c=0; c < data_dictionary[i].items.length; c++) {
      temp.push (data_dictionary[i].items[c].object)
    }
}
result = temp.length

answered May 25, 2016 at 9:28

Parag Bhayani

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1 Comment

Adam Reed Over a year ago

Thanks Parag - just updated it. I had to write out a smaller aspect of the array and did it incorrectly..

Nina Scholz · Accepted Answer · 2016-05-25 09:24:50Z

0

With a proper data structure (there is one }, { missing, as well as some strings are not terminated), you could build an array or just count the occurence.

var data_dictionary = [{ "category": "Food", "items": [{ "object": "Apple", "price": 2.21 }, { "object": "Banana", "price": 1.12, }] }, { "category": "Goods", "items": [{ "object": "Lawnmower", "price": 25.55 }, { "object": "Bicycle", "price": 12.21 }] }],
    result = [];

data_dictionary.forEach(function (a) {
    a.items.forEach(function (b) {
        result.push(b.object);
    });
});

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

answered May 25, 2016 at 9:24

Nina Scholz

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Comments

Nitsan Baleli · Accepted Answer · 2016-05-25 09:25:48Z

if I understood you correctly, you wanted the output as an array with inner arrays lengths.

first you should properly format your data to be valid, then you can iterate over it using the .filter() function for instance:

var data_dictionary = [ {
    "category": "Food",
    "items": [
        {
            "object": "Apple",
            "price": '2.21'
        },
        {
            "object": "Banana",
            "price": '1.12'
        }
     ]
  },
  {
   "category":  "Goods",
   "items":  [
        {
            "object":  "Lawnmower",
            "price":   '25.55'
        },
        {
            "object":  "Bicycle",
            "price":   '12.21'
        }
     ]
  }];


var result = data_dictionary.map(function(n) {
  return n.items.length;
})

console.log(result);

Ravi · Accepted Answer · 2016-05-25 10:20:51Z

0

In your code missing the } and {, create separate object like below.

var data_dictionary = [{"category":"Food",
 "items":[
 {"object":"Apple",
  "price":"2.21"
 },
 {"object":"Banana",
 "price":"1.12"
 }
 ]},

{"category":"Goods",
 "items":[{
  "object":"Lawnmower",
 "price":"25.55"
 },     
{
"object":"Bicycle",
"price":"12.21"
}]
}]
var $data_dictionary = $(data_dictionary);

You can use jQuery to write simple code.

var result = []; 
$data_dictionary.each(function(index,elt){
$(elt.items).each(function(itemIndex, itemElt){
 result.push(itemElt);
});});

here you will get 4 objects

answered May 25, 2016 at 10:20

Ravi

113 bronze badges

Comments

Hussain · Accepted Answer · 2022-03-26 11:31:02Z

0

var object=[];

for(i = 0 ; i < data_dictionary.length; i++)
{
  object.push({'items':data_dictionary[i].object, 'itemsLength':data_dictionary[i].items.length});
}

answered Mar 26, 2022 at 11:31

Hussain

13810 bronze badges

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