Create subsets of an Array using Javascript & Angular JS

Question

I'm trying to create subsets of an Array in a recurring manner. I've an Array in the form of [0,1,2,3,4,5,6]. I'd like to create subsets like [0,1,2], [1,2,3],[2,3,4],[3,4,5],[4,5,6],[5,6,0],[6,0,1],[0,1,2] and so on. But, its not breaking after [4,5,6].

Here is my code

var app = angular.module('app',[]);
app.controller('EventController',function EventController($scope) {
   $scope.count = 0;
   var arr = [], subArr = [], currentIndex;  
   for(var i = 0; i < 7; i++) {
      arr.push(i)
   }
   $scope.next = function() {
   currentIndex = $scope.count;  
   subArr = [];
   $scope.count++;    
   subArr.push(currentIndex);
   subArr.push(currentIndex+1);
   subArr.push(currentIndex+2);
   if(arr.indexOf(currentIndex+1) == -1) {
     console.log(currentIndex+1,'Element not available');
     $scope.count = 0;
     currentIndex = $scope.count
   }
   console.log(subArr);
 } 
});

Here is the fiddle

Any ideas would be greatly appreciated.

Answer 1

Try this:

var app = angular.module('app',[]);
app.controller('EventController',function EventController($scope) {
  $scope.count = 0;
  var  subArr = [], currentIndex; 
  $scope.arr = [];
  for(var i = 0; i < 7; i++) {
    $scope.arr.push(i);
  }

  $scope.next = function() {
    currentIndex = $scope.count;
    //console.log(currentIndex);
    subArr = [];
    $scope.count++;    
    subArr.push(currentIndex);  
    if($scope.arr.indexOf(currentIndex) == $scope.arr.length -2) {
    console.log(currentIndex+2,'Element not available');
       subArr.push(currentIndex+1);
        $scope.count = 0;
     subArr.push($scope.arr[0]);

    }
    else if($scope.arr.indexOf(currentIndex) == $scope.arr.length -1) {
    console.log(currentIndex+1,'Element not available');
     subArr.push($scope.arr[0]);
      subArr.push($scope.arr[1]);
      currentIndex = $scope.count;
    }
        else{
    subArr.push(currentIndex+1);
    subArr.push(currentIndex+2);
    }
    console.log(subArr);
  }
});

Answer 2

The problem is, you are pushing elements before if condition. 1. Move the if block before pushing data to array 2. Change arr.indexOf(currentIndex+1) == -1 to arr.indexOf(currentIndex+2) == -1

var app = angular.module('app',[]);
app.controller('EventController',function EventController($scope) {
  $scope.count = 0;
  var arr = [], subArr = [], currentIndex;  
  for(var i = 0; i < 7; i++) {
    arr.push(i)
  }
  $scope.next = function() {
    currentIndex = $scope.count;
    //console.log(currentIndex);
    subArr = [];
    $scope.count++;

    subArr.push((currentIndex)%arr.length);
    subArr.push((currentIndex+1)%arr.length);
    subArr.push((currentIndex+2)%arr.length);

    console.log(subArr);
  }
});

Answer 3

I guess the below code will help. It is self explanatory.

function createSubset (array, subsetSize, subsets){

  var inputArray = array,
  subset,
  subsetCollection = [],
  noOfSubsets = subsets || inputArray.length + 1,
  size = subsetSize,
  current = 0,
  i;

  while (noOfSubsets--) {    
   subset = [];
   for (i = 0; i < size; i++) {
    subset.push( inputArray[ (current + i) % inputArray.length] );
   }
   current += 1 ;
   subsetCollection.push(subset);
  }

  return subsetCollection;
}

console.log('Test Case start');
var a = [0,1,2,3,4,5,6], 
result = createSubset(a, 3);
console.log(result);
console.log('Test Case end'); 


console.log('Test Case start');
var a = [0,1,2,3,4,5,6], 
result = createSubset(a, 3, 4);
console.log(result);
console.log('Test Case end');