how to get value if keys are matching with array values

Question

I have written one array as below

const OBJECT = {
    '3': 'History And Social Sciences',
    '5': 'Humanities',
    '8': 'Global Studies And Social Impact',
    '10': 'Sanskrit'
};

var rou=[3,5,8,10];

I want to fetch the field values when keys are matching with values. Does anyone have any idea on it?

Jack Bashford · Accepted Answer · 2019-03-15 05:57:15Z

2

map over rou and get the value from OBJECT of that key:

const OBJECT = {
  '3': 'History And Social Sciences',
  '5': 'Humanities',
  '8': 'Global Studies And Social Impact',
  '10': 'Sanskrit',

};

var rou = [3, 5, 8, 10];
var values = rou.map(k => OBJECT[k]);
console.log(values);

answered Mar 15, 2019 at 5:57

Jack Bashford

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1 Comment

Syed Mehtab Hassan Over a year ago

There is a problem if array contains a value that is not present inside the object it will console undefined.

Iakovos Belonias · Accepted Answer · 2019-03-15 05:54:02Z

0

rou[0] is 3 , rou[1] is 5 and so on. What you want is to check if rou[0] that has the value 3, is key to you dictionary.

answered Mar 15, 2019 at 5:54

Iakovos Belonias

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Comments

Ritviz Sharma · Accepted Answer · 2019-03-15 05:56:59Z

0

You can access the value from the object like this

var value = OBJECT.rou[0]

Iterate 'rou' array and for each value of it find the corresponding value in the OBJECT

answered Mar 15, 2019 at 5:56

Ritviz Sharma

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xuexuan wang · Accepted Answer · 2019-03-15 06:34:20Z

0

   Iterator<String> it = jsonObject.keys(); 
   List<Integer> list=new ArrayList();
   while(it.hasNext()){
   int key = it.next(); 
   list.add(key);
   }

answered Mar 15, 2019 at 6:34

xuexuan wang

1

2 Comments

Mani Over a year ago

The question is asked for Javascript and not Java

Nico Haase Over a year ago

Please provide some explanation - what makes you think that this code solves the given problem?

qxg · Accepted Answer · 2019-03-15 06:42:08Z

0

With ramdajs' pick, it's easier.

R.pick(['a', 'd'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1, d: 4}
R.pick(['a', 'e', 'f'], {a: 1, b: 2, c: 3, d: 4}); //=> {a: 1}

If you're interested, check its implementation

answered Mar 15, 2019 at 6:42

qxg

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Comments

Syed Mehtab Hassan · Accepted Answer · 2019-03-15 06:53:27Z

Loop over the object properties and compare if the key is found in arr by indexOf if found get the value of that key.

const OBJECT = {'3': 'History And Social Sciences','5': 'Humanities','8': 'Global Studies And Social Impact','10': 'Sanskrit','a': 'abc'};

var rou = [3, 5, 8, 10];

for (var property in OBJECT) {
  if (OBJECT.hasOwnProperty(property) && rou.indexOf(parseInt(property)) != -1) {

    console.log(OBJECT[property]);
  }
}

You can also do it by iterating the array and if the element of array is present in the object get the value of that object

    const OBJECT = {'3': 'History And Social Sciences','5': 'Humanities','8': 'Global Studies And Social Impact','10': 'Sanskrit','a': 'abc'};

    var rou = [3, 5, 8, 10];

    rou.forEach(function(element) {
      if (OBJECT[element] != undefined) {
        console.log(OBJECT[element]);
      }
    });

wang · Accepted Answer · 2019-03-15 10:19:12Z

0

const OBJECT = {
    '3': 'History And Social Sciences',
    '5': 'Humanities',
    '8': 'Global Studies And Social Impact',
    '10': 'Sanskrit'
};

var rou=[3,5,8,10];

var res = Object.keys(OBJECT).reduce((acc, cur) => rou.indexOf(parseInt(cur)) !== -1 ? (acc.push(OBJECT[cur]), acc) : acc, [])

console.log(res)

answered Mar 15, 2019 at 10:19

wang

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