/// <summary>
/// Transpose <paramref name="source"/>.
/// </summary>
/// <typeparam name="T">Type of element of the nested <see cref="IEnumerable{T}"/>.</typeparam>
/// <param name="source">Sequence which will be transposed.</param>
/// <param name="mode">How non-uniform sequences are handled.</param>
/// <returns>Transposed <paramref name="source"/>.</returns>
public static List <T[]> Transpose <T>(this IList <IList <T> > source, TransposeMode mode = TransposeMode.ErrorOnMissing)
{
if (source is null)
{
throw new ArgumentNullException(nameof(source));
}
if (source.Count == 0)
{
return(new List <T[]>());
}
List <T[]> lines = new List <T[]>();
for (int j = 0; ; j++)
{
T[] line = new T[source.Count];
bool flag = false;
for (int i = 0; i < source.Count; i++)
{
bool value = j < source[i].Count;
flag |= value;
if (value)
{
line[i] = source[i][j];
}
else
{
switch (mode)
{
case TransposeMode.StripOnMissing:
return(lines);
case TransposeMode.DefaultOnMissing:
line[i] = default;
break;
}
}
}
if (flag)
{
if (mode == TransposeMode.ErrorOnMissing)
{
throw new ArgumentOutOfRangeException("All nested enumerators must have same count.", nameof(source));
}
lines.Add(line);
}
else
{
break;
}
}
return(lines);
}
/// <summary>
/// Transpose <paramref name="source"/>.
/// </summary>
/// <typeparam name="T">Type of element of the nested <see cref="IEnumerable{T}"/>.</typeparam>
/// <param name="source">Sequence which will be transposed.</param>
/// <param name="mode">How non-uniform sequences are handled.</param>
/// <returns>Transposed <paramref name="source"/>.</returns>
public static IEnumerable <IEnumerable <T> > Transpose <T>(this IEnumerable <IEnumerable <T> > source, TransposeMode mode = TransposeMode.ErrorOnMissing)
{
// https://stackoverflow.com/a/10555037/7655838 from https://stackoverflow.com/questions/10554866/how-do-you-transpose-dimensions-in-a-2d-collection-using-linq
if (source is null)
{
throw new ArgumentNullException(nameof(source));
}
return(Work());
IEnumerable <IEnumerable <T> > Work()
{
if (!source.Any())
{
yield break;
}
IEnumerator <T>[] enumerators = source.Select(t => t.GetEnumerator()).ToArray();
try
{
T[] line = new T[enumerators.Length];
while (true)
{
bool atLeastOneTrue = false;
bool allTrue = true;
for (int i = 0; i < enumerators.Length; i++)
{
bool value = enumerators[i].MoveNext();
atLeastOneTrue |= value;
allTrue &= value;
if (value)
{
line[i] = enumerators[i].Current;
}
else
{
switch (mode)
{
case TransposeMode.StripOnMissing:
yield break;
case TransposeMode.DefaultOnMissing:
line[i] = default;
break;
}
}
}
if (atLeastOneTrue)
{
if (mode == TransposeMode.ErrorOnMissing && !allTrue)
{
throw new ArgumentOutOfRangeException("All nested enumerators must have same count.", nameof(source));
}
else
{
yield return(line);
}
}
else
{
break;
}
}
}
finally
{
for (int i = 0; i < enumerators.Length; i++)
{
enumerators[i].Dispose();
}
}
}
}
