A for-loop that compares two arrays looking for matching values

Question

I have two arrays that I need to check against each other and if they have reached a point where both items in each array are actually the same as one another, then append s

Answer 1

Hi using lodash or underscore you can easily intersection two array.

_.intersection([2, 1], [2, 3]);

Result is [2].

Lodash document: https://lodash.com/docs/4.17.2#intersection

Answer 2

Here is idea i came up with:

var daysArray = ["1", "2", "3", "4", "5", "12"];
var courseHwork = ["4", "8", "15", "16", "23", "42", "12"];

for (var i = 0; i < courseHwork.length; i++) {
    for (var j = 0; j < daysArray.length; j++) {
        if (courseHwork[i] == daysArray[j]) {
          $('div:contains("'+daysArray[j]+'")').append("<div class='assignment'>"+courseHwork[i]+" - appended</div>");
        }
    }
}

You can find it working here: http://jsfiddle.net/4cqCE/2/

Well, check if that what you want. First it looks for SAME value in 2 arrays, and if it finds it, it appends something to div containing "4" in it. Is that what you want?

Here is an example with 2 same values, with 2 divs, each containing one of the value. http://jsfiddle.net/4cqCE/3/

Answer 3

You can do something like this:

var daysArray = ["1", "2", "3", "4", "5"];
var courseHwork = ["4", "8", "15", "16", "23", "42"];

var arr = daysArray.concat(courseHwork);
var sorted_arr = arr.sort();
var results = [];
for (var i = 0; i < arr.length - 1; i++) {
    if (sorted_arr[i + 1] == sorted_arr[i]) {
        results.push(sorted_arr[i]);
    }
}

console.log(results);

You can run the code here: http://jsfiddle.net/WtEwJ/2/

This will result in a new array results that only contains the duplicate items.

Answer 4

i think you should first create an array intersection and then iterate over the result to do your thing...