Which is the best way to eliminate duplicated items of an array of arrays in javascript?-CodePudding

I have a an array of arrays like this:

let array = [
[402457.9590403921, 4621707.254796494],
[402457.9590403921, 4621707.254796494],
[402457.9590403921, 4621707.254796494],
[402442.9590403921, 462145.254796494],
[402442.9590403921, 462145.254796494],
]

and I would like to delete the repeated items. So it should be:

let array = [
[402457.9590403921, 4621707.254796494],
[402442.9590403921, 462145.254796494],
]

Thanks in advance

CodePudding user response：

Try this, which uses a hash/set to quickly tell what has been seen previously in the search. It's much faster than using indexOf:

const set = new Set();
const outerArr = [
  [402457.9590403921, 4621707.254796494],
  [402457.9590403921, 4621707.254796494],
  [402457.9590403921, 4621707.254796494],
  [402442.9590403921, 462145.254796494],
  [402442.9590403921, 462145.254796494]
];

const newArr = outerArr.filter(innerArr => {
  return innerArr.filter(n => {
    if (set.has(n)) {
      return false;
    }
    
    set.add(n);
    return true;
  }).length;
});
      
   
console.log(newArr);

CodePudding user response：

Convert each item to a string, then use a Set to get unique entries, then parse the string to get an array back.

const strings = array.map(a => JSON.stringify(a));
const unique = new Set(strings);
Array.from(unique, JSON.parse)

CodePudding user response：

Create a set of unique JSON representations of items in the array, and then map those back to objects/arrays.

let array = [
[402457.9590403921, 4621707.254796494],
[402457.9590403921, 4621707.254796494],
[402457.9590403921, 4621707.254796494],
[402442.9590403921, 462145.254796494],
[402442.9590403921, 462145.254796494],
]

console.log([...new Set(array.map(JSON.stringify))].map(JSON.parse))