public static IList <P> PartitionSolveAndMergeBack <T, P>(this IList <T> source, Predicate <T> predicate, Func <IList <T>, IList <P> > matchingPartitionSolver, Func <IList <T>, IList <P> > nonMatchingPartitionSolver)
{
ArgumentUtility.CheckForNull(source, nameof(source));
ArgumentUtility.CheckForNull(predicate, nameof(predicate));
ArgumentUtility.CheckForNull(matchingPartitionSolver, nameof(matchingPartitionSolver));
ArgumentUtility.CheckForNull(nonMatchingPartitionSolver, nameof(nonMatchingPartitionSolver));
var partitionedSource = new PartitionResults <Tuple <int, T> >();
for (int sourceCnt = 0; sourceCnt < source.Count; sourceCnt++)
{
var item = source[sourceCnt];
if (predicate(item))
{
partitionedSource.MatchingPartition.Add(new Tuple <int, T>(sourceCnt, item));
}
else
{
partitionedSource.NonMatchingPartition.Add(new Tuple <int, T>(sourceCnt, item));
}
}
var solvedResult = new List <P>(source.Count);
if (partitionedSource.MatchingPartition.Any())
{
solvedResult.AddRange(matchingPartitionSolver(partitionedSource.MatchingPartition.Select(x => x.Item2).ToList()));
}
if (partitionedSource.NonMatchingPartition.Any())
{
solvedResult.AddRange(nonMatchingPartitionSolver(partitionedSource.NonMatchingPartition.Select(x => x.Item2).ToList()));
}
var result = Enumerable.Repeat(default(P), source.Count).ToList();
if (solvedResult.Count != source.Count)
{
return(solvedResult); // either we can throw here or just return solvedResult and ignore!
}
for (int resultCnt = 0; resultCnt < source.Count; resultCnt++)
{
if (resultCnt < partitionedSource.MatchingPartition.Count)
{
result[partitionedSource.MatchingPartition[resultCnt].Item1] = solvedResult[resultCnt];
}
else
{
result[partitionedSource.NonMatchingPartition[resultCnt - partitionedSource.MatchingPartition.Count].Item1] = solvedResult[resultCnt];
}
}
return(result);
}
/// <summary>
/// Splits an <see cref="IEnumerable{T}"/> into two partitions, determined by the supplied predicate. Those
/// that follow the predicate are returned in the first, with the remaining elements in the second.
/// </summary>
/// <typeparam name="T">The type of the elements of source.</typeparam>
/// <param name="source">The source enumerable to partition.</param>
/// <param name="predicate">The predicate applied to filter the items into their partitions.</param>
/// <returns>An object containing the matching and nonmatching results.</returns>
public static PartitionResults <T> Partition <T>(this IEnumerable <T> source, Predicate <T> predicate)
{
ArgumentUtility.CheckForNull(source, nameof(source));
ArgumentUtility.CheckForNull(predicate, nameof(predicate));
var results = new PartitionResults <T>();
foreach (var item in source)
{
if (predicate(item))
{
results.MatchingPartition.Add(item);
}
else
{
results.NonMatchingPartition.Add(item);
}
}
return(results);
}
