Expand a multi value field in REST API

Question

I have a Sharepoint list that has a multi value field which stores Person or Group.

In the GET call to the Sharepoint list, I get the following response. Collaborators is the name of the field in discussion.

                "Id": 1,
            "ContentTypeId": "0x0100B86E441274F847A599E46276483F9FBB009692E8772BC86A4F8BB8570C018F79BC",
            "Title": "One Microsoft Way",
            "StartDate": "2015-04-15T06:55:19Z",
            "EndDate": "2015-04-15T06:55:19Z",
            "CollaboratorsId": {
                "results": [
                    18
                ]
            },
            "ID": 1,
            "Modified": "2015-04-15T06:55:26Z",
            "Created": "2015-04-15T06:55:26Z",
            "AuthorId": 1,
            "EditorId": 1,

I get an array of IDs in the response, but I wish to expand that field to show the Person or Group name. I tried to use $expand=Collaborators&$select=Collaborators/Title. But this does not work.

Any way to expand the values in a multi-value field?

Answer 1

Try this sample

var call = $.ajax({
    async: false,
    url: _spPageContextInfo.webAbsoluteUrl 
    + "/_api/Web/Lists/GetByTitle('AppointmentInfo')/items"
    + "?$select=Id,Collaborators/Id, Collaborators/Title,Title"
    + "&$expand=Collaborators/Id",
    type: "GET",
    dataType: "json",
    headers: {
      Accept: "application/json;odata=verbose"
    }
});

call.done(function(data, textStatus, jqXHR) {
    var items = data.d.results;
    for (var i = 0; i < items.length; i++) {          
      var CollaboratorsArray = items[i].Collaborators.results;
      for (var j = 0; j < CollaboratorsArray.length; j++) {
        console.log(Collaborators[j].Id + ' - ' + Collaborators[j].Title);
      }       
    }
});

Answer 2

Its should be

$select=Collaborators/Title&$expand=Collaborators

Example your URL should like

 http://yoursite/_api/web/lists/GetByTitle('Employee Details')/items("1")?$select=ManagerName/Title,FirstName,LastName,Position,Phone,Fax,PreviousCompany,Reference,BirthDate,Relocate,EmailAddress&$expand=ManagerName