JavaScript iterate through 2D array and return the mismatches

问题

I have two 2D arrays, I want to compare them using JavaScript, ignore the matches and if there are mismatches to return the entire row into a new array.

    var array1 = [ ['52a1fd0296fc','DEF'],
                 ['52a1fd0296fc','DEF'],
                 ['52a1fd0296fc','DEF'],
                 ['52a1fd0296fc','DEF'],
                 [null,'ABC'],
                 ['6f93cfa0106f','xxx'],
                  ];

    var array2 = [ ['52a1fd0296fc','ABC'],
                   ['6f93cfa0106f','xxx'],
                   ['52a1fd0296fc','ABC'],
                   ['52a1fd0296fc','ABC'],
                   ['52a1fd0296fc','DEF'],
                   ['52a1fd0296fcasd','DEF'],  ];

I want to take this output, the arrays that exists in array2 and NOT in array1:

array3 = [['52a1fd0296fcasd','DEF'],['52a1fd0296fc','ABC']]

Any idea please?

回答1:

Just loop over both arrays:

var array1 = [ ['52a1fd0296fc','DEF'],
                 ['52a1fd0296fc','DEF'],
                 ['52a1fd0296fc','DEF'],
                 ['52a1fd0296fc','DEF'],
                 [null,'ABC'],
                 ['6f93cfa0106f','xxx'],
                 ['52a1fd0296fc','ABC'] ];

var array2 = [ ['52a1fd0296fc','ABC'],
                   ['6f93cfa0106f','xxx'],
                   ['52a1fd0296fc','ABC'],
                   ['52a1fd0296fc','ABC'],
                   ['52a1fd0296fc','DEF'] ];
                   
var array3 = [];
for(var i = 0; i<array1.length; ++i) {
	var a = array1[i];
	var found = false;
	for(var j = 0; j<array2.length; ++j) {
		var b = array2[j];
		if(a[0] == b[0] && a[1] == b[1]) {
			found = true;
			break;
		}
	}
	if(!found) {
		array3.push(a);
	}
}

console.dir(array3);

I assume you want array1 without array2 and not the other way around.

回答2:

Here's my go at it, maybe more compact (and using ES6)

This code removes duplicate arrays from the main array.

var array1 = [ ['52a1fd0296fc','DEF'],
                 ['52a1fd0296fc','DEF'],
                 ['52a1fd0296fc','DEF'],
                 ['52a1fd0296fc','DEF'],
                 [null,'ABC'],
                 ['6f93cfa0106f','xxx'],
                 ['52a1fd0296fc','ABC'] ];

let array3 = []

array1.forEach( a1 => {
	if(!array3.find(a2 => a2[0]===a1[0] && a2[1]===a1[1])) array3.push(a1)
})

console.log(array3)

回答3:

You could use the joined values of the array as key and filter the once of the second array, while indicating already inserted items.

var array1 = [ ['52a1fd0296fc','DEF'], ['52a1fd0296fc','DEF'], ['52a1fd0296fc','DEF'], ['52a1fd0296fc','DEF'], [null,'ABC'], ['6f93cfa0106f','xxx']],
    array2 = [ ['52a1fd0296fc','ABC'], ['6f93cfa0106f','xxx'], ['52a1fd0296fc','ABC'], ['52a1fd0296fc','ABC'], ['52a1fd0296fc','DEF'], ['52a1fd0296fcasd','DEF']],
    hash = Object.create(null),
    result;

array1.forEach(function (a) {
     hash[a.join('|')] = true;
});

result = array2.filter(function (a) {
    return !hash[a.join('|')] && (hash[a.join('|')] = true);
});

console.log(result);

来源：https://stackoverflow.com/questions/44516492/javascript-iterate-through-2d-array-and-return-the-mismatches

标签

javascript

arrays

multidimensional-array