Javascript : Function to return distinct values in a 2D array

Question

I have an array to

var table = [
      {
        country:"india",
        b:2
      },
      {
         country:"usa",
        b:33
      },
       {
         country:"australia",
        b:3
      },
       {
         country:"india",
        b:32
      },
       {
         country:"southafrica",
        b:31
      },
       {
         country:"australia",
        b:30
      },
      {
        country:"india",
        b:40
      }
    ];

result expected :

 var table = [
      {
        country:"india",
        b:2
      },
      {
         country:"usa",
        b:33
      },
       {
         country:"australia",
        b:3
      }, 
       {
         country:"southafrica",
        b:31
      }

    ];

My code is :

function getUniqueValuesOfKey(array, key){
  return array.reduce(function(carry, item){
    if(item[key] && !~carry.indexOf(item[key])) carry.push(item[key]);
    return carry;
  }, []);
}

document.write(JSON.stringify(getUniqueValuesOfKey(table, 'a')));

how to get the unique array result based on the country key

your input has no "a" keys

Matt Ellen
– Matt Ellen

2019-08-29 13:36:48 +00:00
Commented Aug 29, 2019 at 13:36 — Matt Ellen
– Matt Ellen, Commented Aug 29, 2019 at 13:36

Shubham Dixit · Accepted Answer · 2019-08-29 13:37:34Z

2

Try this ,With Array reduce and Filter.Hope It helps

var table = [{
  country: "india",
  b: 2
}, {
  country: "usa",
  b: 33
}, {
  country: "australia",
  b: 3
}, {
  country: "india",
  b: 32
}, {
  country: "southafrica",
  b: 31
}, {
  country: "australia",
  b: 30
}, {
  country: "india",
  b: 40
}];

let result = table.reduce((acc, ele) => {
  if (acc.filter(el => el.country == ele.country).length == 0) {
    acc.push(ele)
  }
  return acc;

}, [])
console.log(result)

answered Aug 29, 2019 at 13:37

Shubham Dixit

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Comments

Mohammad Usman · Accepted Answer · 2019-08-29 13:47:41Z

0

You can use .filter() to get the filtered array:

const data = [ { country:"india", b:2 }, { country:"usa", b:33 }, { country:"australia", b:3 }, { country:"india", b:32 }, { country:"southafrica", b:31 }, { country:"australia", b:30 }, { country:"india", b:40 } ];

const getUniqueData = (arr, names = []) => arr.filter(({ country }) => (
  names.includes(country) ?
  false :
  (names.push(country), true)
));

console.log(getUniqueData(data));

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

answered Aug 29, 2019 at 13:47

Mohammad Usman

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Comments

AndichamyGA · Accepted Answer · 2019-08-29 13:53:57Z

0

Simple solution with o(n) time complexity.

var table = [{
  country: "india",
  b: 2
}, {
  country: "usa",
  b: 33
}, {
  country: "australia",
  b: 3
}, {
  country: "india",
  b: 32
}, {
  country: "southafrica",
  b: 31
}, {
  country: "australia",
  b: 30
}, {
  country: "india",
  b: 40
}];

let result = [];
const countries = {};

for(let item of table) {
    let {country, b} = item;
    if(!countries[country]) {
        countries[country] = b;
        result.push(item);
    }
}

console.log(result);

answered Aug 29, 2019 at 13:53

AndichamyGA

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Comments

Neel Rathod · Accepted Answer · 2019-08-29 14:10:37Z

0

You can simply achieve this with one for loop.

const table = [{
country: 'india',
b: 2
}, {
country: 'usa',
b: 33
}, {
country: 'australia',
b: 3
}, {
country: 'india',
b: 32
}, {
country: 'southafrica',
b: 31
}, {
country: 'australia',
b: 30
}, {
country: 'india',
b: 40
}];

const getUniqueArray = (array, tempObj = {}) => {
  const uniqueArray = [];
  for (let i = 0; i < array.length; i += 1) {
    const element = array[i];
    const { country, b } = element;
    if (!tempObj[country]) {
      tempObj[country] = b;
      uniqueArray.push(element);
    }
  }
  return uniqueArray;
};
const result = getUniqueArray(table);
console.log(result);

answered Aug 29, 2019 at 14:10

Neel Rathod

2,11115 silver badges29 bronze badges

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