使用javascript过滤器从数组中删除元素

Question

I have two arrays and want to remove duplicates using filter function.

Here is my code:

 arr1 = [1, 2, 3, 1, 2, 3]; arr2 = [2, 3]; result = [1, 1]; var result = arr1.filter(function(value, index) { for (var i = 0; i <= arr2.length; i++) { if (value !== arr2[i]) { return value === arr2[i]; } } }

Thanks in advance! Any help would be great!

Answer 1

You can try to convert arguments into array and then check if the value from the initial array is in arguments array:

function destroyer(arr) {

  // Converting arguments into array
  var args = Array.prototype.slice.call(arguments);

  arr = arr.filter(function (val) {
    return args.includes(val)===false;
  });

    return arr;
}


destroyer([1, 2, 3, 1, 2, 3], 2, 3); // returns[1,1]

Answer 2

First of all, if its not a problem adding a library. I am using uniq from underscore.js .

uniq_.uniq(array, [isSorted], [iteratee]) Alias: unique

Produces a duplicate-free version of the array, using === to test object equality. In particular only the first occurence of each value is kept. If you know in advance that the array is sorted, passing true for isSorted will run a much faster algorithm. If you want to compute unique items based on a transformation, pass an iteratee function.

_.uniq([1, 2, 1, 4, 1, 3]); => [1, 2, 4, 3]

Other solution is using pure JS:

var newArray = [1, 2, 2, 3, 3, 4, 5, 6];
   var unique = newArray.filter(function(itm, i, a) {
      return i == newArray.indexOf(itm);
   });
   alert(unique);

But first you will need to combine your arrays in a new array:

var newArray = arr1.concat(arr2);

JS Fiddle

I hope this helped! :)

Answer 3

Here's one way without the filter function:

var arr1 = [1, 2, 3, 1, 2, 3];
var newArr = [];
for(var i = 0;i < arr1.length;i++){
    if (newArr.indexOf(arr1[i]) === -1) {
        newArr.push(arr1[i]);
    }
}

Answer 4

As in this JS Fiddle , using filter()

 arr1 = [1, 2, 3, 1, 2, 3]; arr2 = [2, 3]; result = [1, 1]; var result = arr1.filter(myFunc); function myFunc(value) { for (var i = 0; i < arr2.length; ++i) { // to remove every occurrence of the matched value for (var j = arr1.length; j--;) { if (arr1[j] === arr2[i]) { // remove the element arr1.splice(j, 1); } } } } document.getElementById('result').innerHTML = arr1; console.log(arr1); // Output: [1,1]

 <div id="result"></div>

Answer 5

Just use Array.prototype.filter()

The filter() method creates a new array with all elements that pass the test implemented by the provided function.

with Array.prototype.indexOf()

The indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.

 var arr1 = [1, 2, 3, 1, 2, 3], arr2 = [2, 3], result = arr1.filter(function (a) { return !~arr2.indexOf(a); }); document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');