How to find the difference between 2 IEnumerable objects

Question

I have 2 lists of names:

IEnumerable<dynamic> userids = null;
IEnumerable<dynamic> lsCheckedUsers = null;

The list of users and lsCheckedUsers is populated from the SQL database using dapper.

Now I want to find all userid that are not in lsCheckedUsers.

I tried the following

var userdifference = userids.Where(i => !lsCheckedUsers.Contains(lsCheckedUsers));
var userdifference = userids.Except(lsCheckedUsers);

None of the above actual values returns the difference between 2.

How to get the difference between sheets that do not exist in both.

I'm sure lsCheckedUsers have Guids that are in userid

+5

user1526912 Mar 27 '13 at 18:17

4 answers

- .

var difference = list1.Where (e => !list2.Any(a => a == e))

+2

:

var userdifference = userids.Where(i => !lsCheckedUsers.Contains(lsCheckedUsers));

, :

var userdifference = userids.Where(i => !lsCheckedUsers.Contains(i));

Update:

, - "" , , Guid , -. , :

var guid = Guid.NewGuid();
var guids = new[] { new Guid(guid.ToString()) };

Console.WriteLine(guids.Contains(guid));

, True.

+1

itsme86 27 . '13 18:22

Except

String GUID.
.

HashSet ExceptWith, , .
HashSet, .

+1

paparazzo 27 . '13 18:43

Ian Gardner · Accepted Answer · 2013-03-27T18:51:06+0000

It is right:

var userdifference = userids.Except(lsCheckedUsers);

It will work if both of your IEnumerable<dynamic>contain Guids. Print or check the items in each to make sure they are Guids.

IEnumerable<Guid> Guids, , . , , .