split List<User> in multiple List<User> in c# - list

Question

I want to split List of user generic List into its small list with each 5 records.
Ex
I have List: u1,u2,u3,u4,u5,u6,u7,u8,u9,u10,u11,u12,u13,u14,u15.
so must be split into
List1:u1,u2,u3,u4,u5
List2:u6,u7,u8,u9,u10
List3:u11,u12,u13,u14,u15
Any direct method available or need programing logic in c# ?

Answer 1

You can group on the index:
List<List<User>> lists =
list
.Select((u, i) => new { List = i / 5, User = u })
.GroupBy(g => g.List, g => g.User)
.Select(g => g.ToList())
.ToList();
You can also use Range to make a loop and get a part of the list for each iteration:
List<List<User>> lists =
Enumerable.Range(0, (list.Count + 4) / 5)
.Select(n => list.Skip(n * 5).Take(5).ToList())
.ToList();

Answer 2

You can Use Skip(count) and Take(count) methods.

Answer 3

// These are your objects, put here your init code
var list = Enumerable.Range(1, 20).ToList();
var lists = new List<int>[(list.Count + 4) / 5]; // The array of lists you wanted
for (int i = 0; i < lists.Length; i++)
{
lists[i] = list.Skip(i * 5).Take(5).ToList();
}
The (list.Count + 4) / 5 is a method to round UP the division (if I have 6 elements in list, I want two sublists)
If you really need a List of List...
var lists = new List<List<int>>((list.Count + 4) / 5);
for (int i = 0; i < lists.Capacity; i++)
{
lists.Add(list.Skip(i * 5).Take(5).ToList());
}

Answer 4

I think this might be more efficient since you're not doing groupings, orderings and such. This is just a single iteration over the dataset.
var splitList= new List<IEnumerable<User>>();
List<User> currentList = null;
int count = 0;
foreach(var user in users)
{
if (0 == count% 5)
{
currentList = new List<User>(5);
returnValue.Add(currentList);
}
currentList.Add(key);
count++;
}
return returnValue;