Concat

Returns a new collection that contains the elements of each the collection in order.

Parameters	Returns
IEnumerable<IEnumerable<T>> sources	IEnumerable<T>
params IEnumerable<T>[ ] sources	IEnumerable<T>

Usage

There's two different overloads of this function, but they works in a very similar way.

The first one requires that the parameter is an IEnumerable of IEnumerables and the second one uses the params keyword to provides a way to inform multiples standalone IEnumerables.

Concatenating an IEnumerable of IEnumerabls

//IEnumerable<IEnumerable<int>> sources = 
//    { { 1, 2, 3, 4, 5 }, { 6, 7, 8, 9, 10 } }

IEnumerable<int> result = sources.Concat()

//result = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }

Concatenating three different collections

//IEnumerable<int> first = { 6, 7, 8, 9, 10 }
//IEnumerable<int> second = { 1, 2, 3, 4, 5 }
//IEnumerable<int> third = { 2, 4, 6, 8, 10 }

IEnumerable<int> result = first.Concat(second, third);

//result = { 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 2, 4, 6, 8, 10 }