Array Set union and intersection - Node.js Data Structure

Node.js examples for Data Structure:Set

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Description

Array Set union and intersection

Demo Code


/**/*  w w  w. j ava2 s.c  o  m*/
 * Retrieve the union set of a bunch of arrays
 * @param {Array} array1,... the arrays to unify
 * @return {Array} the union set
 */
Array.union = function() {
   var result = [];
   var map = {};
   for (var i=0; i<arguments.length; i+=1) {
      for (var n in arguments[i]) {
         var item = arguments[i][n];
         if (!map[item]) {
            result.push(item);
            map[item] = true;
         }
      }
   }
   return result;
};

/**
 * Retrieve the intersection set of a bunch of arrays
 * @param {Array} array1,... the arrays to intersect
 * @return {Array} the intersection set
 */
Array.intersection = function() {
   var all = Array.union.apply(this, arguments);
   var result = [];
   for (var n in all) {
      var chksum = 0;
      var item = all[n];
      for (var i=0; i<arguments.length; i+=1) {
         if (arguments[i].contains(item))
            chksum += 1;
         else
            break;
      }
      if (chksum == arguments.length)
         result.push(item);
   }
   return result;
};

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