Question

143

Comparing two arrays which contain objects

rated 0 times [ 144] [ 1] / answers: 1 / hits: 22947 / 11 Years ago, sun, january 19, 2014, 12:00:00

I have two arrays which only contain objects for groups. One contains all the groups on my site. The other contains all the groups a specific user belongs to.

I'd like to subtract: All the groups - user groups = groups remaining

I'm using AngularJS, I'm not sure if that helps here or not (maybe a filter could be used).

I looked at previous questions and came across some options:

These are the ones I tried:

$scope.availableGroups =  $($scope.groups).not($scope.assignedGroups).get();

$scope.availableGroups = $.grep($scope.groups,function(x) {return $.inArray(x, $scope.assignedGroups) < 0})

This is one of the arrays:

assignedGroups:

[{

    id: 115,

    name: 'Test Group 2',

    Description: '',

    owner: 10,

    OwnerIsUser: false,

}, {

    id: 116,

    name: 'Test Group 3',

    Description: '',

    owner: 71,

    OwnerIsUser: false,

}, {

    id: 117,

    name: 'Test Group 4',

    Description: '',

    owner: 71,

    OwnerIsUser: false,

}, {

    id: 118,

    name: 'Test Group 5',

    Description: '',

    owner: 115,

    OwnerIsUser: false,

}, {

    id: 119,

    name: 'Test Group 6',

    Description: '',

    owner: 8,

    OwnerIsUser: true,

}];

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gilbertomaximilianod

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3 Years ago

answered 11 Years ago bryantc · Accepted Answer

I think you should extract ids to an object first and then compare two objects. Eg:

var assignedGroupsIds = {};

var groupsIds = {};

var result = [];



$scope.assignedGroups.forEach(function (el, i) {

  assignedGroupsIds[el.id] = $scope.assignedGroups[i];

});



$scope.groups.forEach(function (el, i) {

  groupsIds[el.id] = $scope.groups[i];

});



for (var i in groupsIds) {

    if (!assignedGroupsIds.hasOwnProperty(i)) {

        result.push(groupsIds[i]);

    }

}



return result;

Here goes simplified fiddle: http://jsfiddle.net/NLQGL/2/
Adjust it to your needs.

I think it's a good solution since you could reuse the groupsIds object (it seems not to change often).

Note: Feel free to use angular.forEach() instead of Array.prototype.forEach