Interleaving multiple (more than 2) irregular lists using LINQ
c#, linq
Solution
What you're describing is essentially a Transpose Method where overhanging items are included and the result is flattened. Here's my attempt:
static IEnumerable<IEnumerable<T>> TransposeOverhanging<T>(
this IEnumerable<IEnumerable<T>> source)
{
var enumerators = source.Select(e => e.GetEnumerator()).ToArray();
try
{
T[] g;
do
{
yield return g = enumerators
.Where(e => e.MoveNext()).Select(e => e.Current).ToArray();
}
while (g.Any());
}
finally
{
Array.ForEach(enumerators, e => e.Dispose());
}
}
Example:
var result = items.TransposeOverhanging().SelectMany(g => g).ToList();
// result == { 1, 5, 7, 2, 6, 8, 3, 9, 4 }
Problem
Say I have the following data ``` IEnumerable<IEnumerable<int>> items = new IEnumerable<int>[] { new int[] { 1, 2, 3, 4 }, new int[] { 5, 6 }, new int[] { 7, 8, 9 } }; ``` What would be the easiest way to return a flat list with the items interleaved so I'd get the result: 1, 5, 7, 2, 6, 8, 3, 9, 4 Note: The number of inner lists is not known at runtime.