javascript - How can I find all arrays with the same values? -

i have array several arrays inside him, that:

var arrs = [   ['qqq', 5],   ['www', 2],   ['qqq', 15],   ['qqq', 11],   ['www', 1],   ['eee', 22] ]; 

how can find arrays same values , sum them 1 array, that:

[     ['qqq', 31],     ['www', 3] ]; 

any appreciated!

you should use new "results" array store output. loop input array , either add results (if new one), or update results if match found.

something this:

var arrs = [     ['qqq', 5],     ['www', 2],     ['qqq', 15],     ['qqq', 11],     ['www', 1],     ['eee', 22] ];  function sumduplicates(arr) {     var results = [];//array hold results     //loop input array can process each item     (var = 0; < arr.length; i++) {         var current = arr[i];//get current item processing         var match = null;//this hold match, if find 1         //loop results existing match         (var j = 0; j < results.length; j++) {             var item = results[j];//get item in results want check match             //check if have found match             if (item[0] === current[0]) {                 match = item;//match found store match later                 break;//match found break loop             }         }         //no match found, add current item results (so can matched later)         if (!match) results.push(current);         //match found, increment stored value         else match[1] = match[1] + current[1];     }      return results; }  var result = sumduplicates(arrs); console.log(result); 

here working example

note include non-duplicates (such 'eee'), makes sense me. if reason need remove items without duplicates let me know