How to compare two arrays for equality?

Question

I have not found an answer to the simplest case possible. I know there are lots of questions like that but all of them have a higher degree of complexity. In my case, the arrays are very similar in the following respects:

the same number of elements
all the elements are of the same kind,
the elements consist only of integers 0 and 1

The code I have is:

var mearr = [
  [1, 1, 0, 1, 1, 0],
  [1, 1, 1, 0, 1, 0],
  [1, 1, 1, 0, 0, 1],
  [0, 1, 0, 0, 1, 1],
  [1, 1, 1, 0, 1, 0],
  [1, 0, 0, 1, 0, 1]
];

for (i=0;i<mearr.length/2;i++) {
    var l = mearr[i];
    var r = mearr[i+3];
    var same = (l == r) ? "Same" : "different";
    console.log(l, r, same);
}

I'd assume that the second and fifth elements would return "Same", but they do not.

@JarrodRoberson It is not a duplicate, since this is totally a different case. The first half part of array is compared with the second half part. Correct me if I am wrong. — Praveen Kumar Purushothaman, Dec 24 '15 at 18:37
@PraveenKumar - you are wrong, because you are not reading the code for comprehension. — , Dec 24 '15 at 19:54

score 1 · Accepted Answer · answered Dec 24 '15 at 18:23

1

For this case, I would suggest you to .join() and compare as strings!

var mearr = [
  [1, 1, 0, 1, 1, 0],
  [1, 1, 1, 0, 1, 0],
  [1, 1, 1, 0, 0, 1],
  [0, 1, 0, 0, 1, 1],
  [1, 1, 1, 0, 1, 0],
  [1, 0, 0, 1, 0, 1]
];

for (i = 0; i < mearr.length / 2; i++) {
  var l = mearr[i].join("");
  var r = mearr[i+(mearr.length/2)].join("");
  var same = (l == r) ? "Same" : "different";
  console.log(l, r, same);
}

And yes, yay! It worked:

110110 010011 different
111010 111010 Same
111001 100101 different

Note: As you said, this works only for an array with binary numbers like this. For this case only!

answered Dec 24 '15 at 18:23

Praveen Kumar Purushothaman

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Thank you. Having researched it before asking this question, I have seen answers discouraging from converting arrays to strings to do the comparison but, as you say, this would probably be the easiest way in this particular case. Thank you. – Wasteland Dec 24 '15 at 18:29
@Wasteland You are right. But yeah, **for this case**, keep in mind. Don't use the solution for anything else. `:)` – Praveen Kumar Purushothaman Dec 24 '15 at 18:30
So yes, welcoming all the downvotes. Kindly say the reason please? – Praveen Kumar Purushothaman Dec 24 '15 at 18:34
1

it works for any numbers or strings, not just "binary numbers"... – dandavis Dec 24 '15 at 19:19
@dandavis Yes, it does. – Praveen Kumar Purushothaman Dec 24 '15 at 19:20

How to compare two arrays for equality?

1 Answers1