private static HashSet <long> PerformMerging(DataFrame retainedDataFrame, string[] retainedJoinColumnNames,
Dictionary <long, ICollection <long> > occurrences, HashSet <long> supplementaryJoinColumnsNullIndices,
out PrimitiveDataFrameColumn <long> retainedRowIndices, out PrimitiveDataFrameColumn <long> supplementaryRowIndices,
bool isInner, bool calculateIntersection)
{
retainedRowIndices = new Int64DataFrameColumn("RetainedIndices");
supplementaryRowIndices = new Int64DataFrameColumn("SupplementaryIndices");
HashSet <long> intersection = calculateIntersection ? new HashSet <long>() : null;
var retainJoinColumns = retainedJoinColumnNames.Select(name => retainedDataFrame.Columns[name]).ToArray();
for (long i = 0; i < retainedDataFrame.Columns.RowCount; i++)
{
if (!IsAnyNullValueInColumns(retainJoinColumns, i))
{
// Get all row indexes from supplementary dataframe that satisfy JOIN condition
if (occurrences.TryGetValue(i, out ICollection <long> rowIndices))
{
foreach (long supplementaryRowIndex in rowIndices)
{
retainedRowIndices.Append(i);
supplementaryRowIndices.Append(supplementaryRowIndex);
// Store intersection if required
if (calculateIntersection)
{
if (!intersection.Contains(supplementaryRowIndex))
{
intersection.Add(supplementaryRowIndex);
}
}
}
}
else
{
if (isInner)
{
continue;
}
retainedRowIndices.Append(i);
supplementaryRowIndices.Append(null);
}
}
else
{
foreach (long row in supplementaryJoinColumnsNullIndices)
{
retainedRowIndices.Append(i);
supplementaryRowIndices.Append(row);
}
}
}
return(intersection);
}
private static void AppendDataFrameColumnFromArrowArray(Field field, IArrowArray arrowArray, DataFrame ret, string fieldNamePrefix = "")
{
IArrowType fieldType = field.DataType;
DataFrameColumn dataFrameColumn = null;
string fieldName = fieldNamePrefix + field.Name;
switch (fieldType.TypeId)
{
case ArrowTypeId.Boolean:
BooleanArray arrowBooleanArray = (BooleanArray)arrowArray;
ReadOnlyMemory <byte> valueBuffer = arrowBooleanArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> nullBitMapBuffer = arrowBooleanArray.NullBitmapBuffer.Memory;
dataFrameColumn = new BooleanDataFrameColumn(fieldName, valueBuffer, nullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Double:
PrimitiveArray <double> arrowDoubleArray = (PrimitiveArray <double>)arrowArray;
ReadOnlyMemory <byte> doubleValueBuffer = arrowDoubleArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> doubleNullBitMapBuffer = arrowDoubleArray.NullBitmapBuffer.Memory;
dataFrameColumn = new DoubleDataFrameColumn(fieldName, doubleValueBuffer, doubleNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Float:
PrimitiveArray <float> arrowFloatArray = (PrimitiveArray <float>)arrowArray;
ReadOnlyMemory <byte> floatValueBuffer = arrowFloatArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> floatNullBitMapBuffer = arrowFloatArray.NullBitmapBuffer.Memory;
dataFrameColumn = new SingleDataFrameColumn(fieldName, floatValueBuffer, floatNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Int8:
PrimitiveArray <sbyte> arrowsbyteArray = (PrimitiveArray <sbyte>)arrowArray;
ReadOnlyMemory <byte> sbyteValueBuffer = arrowsbyteArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> sbyteNullBitMapBuffer = arrowsbyteArray.NullBitmapBuffer.Memory;
dataFrameColumn = new SByteDataFrameColumn(fieldName, sbyteValueBuffer, sbyteNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Int16:
PrimitiveArray <short> arrowshortArray = (PrimitiveArray <short>)arrowArray;
ReadOnlyMemory <byte> shortValueBuffer = arrowshortArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> shortNullBitMapBuffer = arrowshortArray.NullBitmapBuffer.Memory;
dataFrameColumn = new Int16DataFrameColumn(fieldName, shortValueBuffer, shortNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Int32:
PrimitiveArray <int> arrowIntArray = (PrimitiveArray <int>)arrowArray;
ReadOnlyMemory <byte> intValueBuffer = arrowIntArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> intNullBitMapBuffer = arrowIntArray.NullBitmapBuffer.Memory;
dataFrameColumn = new Int32DataFrameColumn(fieldName, intValueBuffer, intNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Int64:
PrimitiveArray <long> arrowLongArray = (PrimitiveArray <long>)arrowArray;
ReadOnlyMemory <byte> longValueBuffer = arrowLongArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> longNullBitMapBuffer = arrowLongArray.NullBitmapBuffer.Memory;
dataFrameColumn = new Int64DataFrameColumn(fieldName, longValueBuffer, longNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.String:
StringArray stringArray = (StringArray)arrowArray;
ReadOnlyMemory <byte> dataMemory = stringArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> offsetsMemory = stringArray.ValueOffsetsBuffer.Memory;
ReadOnlyMemory <byte> nullMemory = stringArray.NullBitmapBuffer.Memory;
dataFrameColumn = new ArrowStringDataFrameColumn(fieldName, dataMemory, offsetsMemory, nullMemory, stringArray.Length, stringArray.NullCount);
break;
case ArrowTypeId.UInt8:
PrimitiveArray <byte> arrowbyteArray = (PrimitiveArray <byte>)arrowArray;
ReadOnlyMemory <byte> byteValueBuffer = arrowbyteArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> byteNullBitMapBuffer = arrowbyteArray.NullBitmapBuffer.Memory;
dataFrameColumn = new ByteDataFrameColumn(fieldName, byteValueBuffer, byteNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.UInt16:
PrimitiveArray <ushort> arrowUshortArray = (PrimitiveArray <ushort>)arrowArray;
ReadOnlyMemory <byte> ushortValueBuffer = arrowUshortArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> ushortNullBitMapBuffer = arrowUshortArray.NullBitmapBuffer.Memory;
dataFrameColumn = new UInt16DataFrameColumn(fieldName, ushortValueBuffer, ushortNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.UInt32:
PrimitiveArray <uint> arrowUintArray = (PrimitiveArray <uint>)arrowArray;
ReadOnlyMemory <byte> uintValueBuffer = arrowUintArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> uintNullBitMapBuffer = arrowUintArray.NullBitmapBuffer.Memory;
dataFrameColumn = new UInt32DataFrameColumn(fieldName, uintValueBuffer, uintNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.UInt64:
PrimitiveArray <ulong> arrowUlongArray = (PrimitiveArray <ulong>)arrowArray;
ReadOnlyMemory <byte> ulongValueBuffer = arrowUlongArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> ulongNullBitMapBuffer = arrowUlongArray.NullBitmapBuffer.Memory;
dataFrameColumn = new UInt64DataFrameColumn(fieldName, ulongValueBuffer, ulongNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Struct:
StructArray structArray = (StructArray)arrowArray;
StructType structType = (StructType)field.DataType;
IEnumerator <Field> fieldsEnumerator = structType.Fields.GetEnumerator();
IEnumerator <IArrowArray> structArrayEnumerator = structArray.Fields.GetEnumerator();
while (fieldsEnumerator.MoveNext() && structArrayEnumerator.MoveNext())
{
AppendDataFrameColumnFromArrowArray(fieldsEnumerator.Current, structArrayEnumerator.Current, ret, field.Name + "_");
}
break;
case ArrowTypeId.Decimal:
case ArrowTypeId.Binary:
case ArrowTypeId.Date32:
case ArrowTypeId.Date64:
case ArrowTypeId.Dictionary:
case ArrowTypeId.FixedSizedBinary:
case ArrowTypeId.HalfFloat:
case ArrowTypeId.Interval:
case ArrowTypeId.List:
case ArrowTypeId.Map:
case ArrowTypeId.Null:
case ArrowTypeId.Time32:
case ArrowTypeId.Time64:
default:
throw new NotImplementedException(nameof(fieldType.Name));
}
if (dataFrameColumn != null)
{
ret.Columns.Insert(ret.Columns.Count, dataFrameColumn);
}
}
private static DataFrameColumn CreateColumn(Type kind, string[] columnNames, int columnIndex)
{
DataFrameColumn ret;
if (kind == typeof(bool))
{
ret = new BooleanDataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(int))
{
ret = new Int32DataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(float))
{
ret = new SingleDataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(string))
{
ret = new StringDataFrameColumn(GetColumnName(columnNames, columnIndex), 0);
}
else if (kind == typeof(long))
{
ret = new Int64DataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(decimal))
{
ret = new DecimalDataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(byte))
{
ret = new ByteDataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(char))
{
ret = new CharDataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(double))
{
ret = new DoubleDataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(sbyte))
{
ret = new SByteDataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(short))
{
ret = new Int16DataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(uint))
{
ret = new UInt32DataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(ulong))
{
ret = new UInt64DataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else if (kind == typeof(ushort))
{
ret = new UInt16DataFrameColumn(GetColumnName(columnNames, columnIndex));
}
else
{
throw new NotSupportedException(nameof(kind));
}
return(ret);
}
private Int64DataFrameColumn GetSortIndices(IComparer <T> comparer, out Int64DataFrameColumn columnNullIndices)
{
List <List <int> > bufferSortIndices = new List <List <int> >(_columnContainer.Buffers.Count);
columnNullIndices = new Int64DataFrameColumn("NullIndices", NullCount);
long nullIndicesSlot = 0;
// Sort each buffer first
for (int b = 0; b < _columnContainer.Buffers.Count; b++)
{
ReadOnlyDataFrameBuffer <T> buffer = _columnContainer.Buffers[b];
ReadOnlySpan <byte> nullBitMapSpan = _columnContainer.NullBitMapBuffers[b].ReadOnlySpan;
int[] sortIndices = new int[buffer.Length];
for (int i = 0; i < buffer.Length; i++)
{
sortIndices[i] = i;
}
IntrospectiveSort(buffer.ReadOnlySpan, buffer.Length, sortIndices, comparer);
// Bug fix: QuickSort is not stable. When PrimitiveDataFrameColumn has null values and default values, they move around
List <int> nonNullSortIndices = new List <int>();
for (int i = 0; i < sortIndices.Length; i++)
{
int localSortIndex = sortIndices[i];
if (_columnContainer.IsValid(nullBitMapSpan, localSortIndex))
{
nonNullSortIndices.Add(sortIndices[i]);
}
else
{
columnNullIndices[nullIndicesSlot] = localSortIndex + b * _columnContainer.Buffers[0].Length;
nullIndicesSlot++;
}
}
bufferSortIndices.Add(nonNullSortIndices);
}
// Simple merge sort to build the full column's sort indices
ValueTuple <T, int> GetFirstNonNullValueAndBufferIndexStartingAtIndex(int bufferIndex, int startIndex)
{
int index = bufferSortIndices[bufferIndex][startIndex];
T value;
ReadOnlyMemory <byte> buffer = _columnContainer.Buffers[bufferIndex].ReadOnlyBuffer;
ReadOnlyMemory <T> typedBuffer = Unsafe.As <ReadOnlyMemory <byte>, ReadOnlyMemory <T> >(ref buffer);
if (!typedBuffer.IsEmpty)
{
bool isArray = MemoryMarshal.TryGetArray(typedBuffer, out ArraySegment <T> arraySegment);
if (isArray)
{
value = arraySegment.Array[index + arraySegment.Offset];
}
else
{
value = _columnContainer.Buffers[bufferIndex][index];
}
}
else
{
value = _columnContainer.Buffers[bufferIndex][index];
}
return(value, startIndex);
}
SortedDictionary <T, List <ValueTuple <int, int> > > heapOfValueAndListOfTupleOfSortAndBufferIndex = new SortedDictionary <T, List <ValueTuple <int, int> > >(comparer);
IList <ReadOnlyDataFrameBuffer <T> > buffers = _columnContainer.Buffers;
for (int i = 0; i < buffers.Count; i++)
{
ReadOnlyDataFrameBuffer <T> buffer = buffers[i];
if (bufferSortIndices[i].Count == 0)
{
// All nulls
continue;
}
ValueTuple <T, int> valueAndBufferIndex = GetFirstNonNullValueAndBufferIndexStartingAtIndex(i, 0);
if (heapOfValueAndListOfTupleOfSortAndBufferIndex.ContainsKey(valueAndBufferIndex.Item1))
{
heapOfValueAndListOfTupleOfSortAndBufferIndex[valueAndBufferIndex.Item1].Add((valueAndBufferIndex.Item2, i));
}
else
{
heapOfValueAndListOfTupleOfSortAndBufferIndex.Add(valueAndBufferIndex.Item1, new List <ValueTuple <int, int> >()
{
(valueAndBufferIndex.Item2, i)
});
internal override PrimitiveDataFrameColumn <long> GetAscendingSortIndices(out Int64DataFrameColumn nullIndices)
{
Int64DataFrameColumn sortIndices = GetSortIndices(Comparer <T> .Default, out nullIndices);
return(sortIndices);
}
private static HashSet <long> Merge(DataFrame retainedDataFrame, DataFrame supplementaryDataFrame, string[] retainedJoinColumnNames, string[] supplemetaryJoinColumnNames, out PrimitiveDataFrameColumn <long> retainedRowIndices, out PrimitiveDataFrameColumn <long> supplementaryRowIndices, bool isInner = false, bool calculateIntersection = false)
{
if (retainedJoinColumnNames == null)
{
throw new ArgumentNullException(nameof(retainedJoinColumnNames));
}
if (supplemetaryJoinColumnNames == null)
{
throw new ArgumentNullException(nameof(supplemetaryJoinColumnNames));
}
if (retainedJoinColumnNames.Length != supplemetaryJoinColumnNames.Length)
{
throw new ArgumentException(Strings.MismatchedArrayLengths, nameof(retainedJoinColumnNames));
}
HashSet <long> intersection = calculateIntersection ? new HashSet <long>() : null;
// Get occurrences of values in columns used for join in the retained and supplementary dataframes
Dictionary <long, ICollection <long> > occurrences = null;
Dictionary <long, long> retainedIndicesReverseMapping = null;
HashSet <long> supplementaryJoinColumnsNullIndices = new HashSet <long>();
for (int colNameIndex = 0; colNameIndex < retainedJoinColumnNames.Length; colNameIndex++)
{
DataFrameColumn shrinkedRetainedColumn = retainedDataFrame.Columns[retainedJoinColumnNames[colNameIndex]];
//shrink retained column by row occurrences from previous step
if (occurrences != null)
{
//only rows with occurences from previose step should go for futher processing
var shrinkedRetainedIndices = occurrences.Keys.ToArray();
//create reverse mapping of index of the row in the shrinked column to the index of this row in the original dataframe (new index -> original index)
var newRetainedIndicesReverseMapping = new Dictionary <long, long>(shrinkedRetainedIndices.Length);
for (int i = 0; i < shrinkedRetainedIndices.Length; i++)
{
//store reverse mapping to restore original dataframe indices from indices in shrinked row
var originalIndex = shrinkedRetainedIndices[i];
newRetainedIndicesReverseMapping.Add(i, originalIndex);
}
retainedIndicesReverseMapping = newRetainedIndicesReverseMapping;
shrinkedRetainedColumn = shrinkedRetainedColumn.Clone(new Int64DataFrameColumn("Indices", shrinkedRetainedIndices));
}
DataFrameColumn supplementaryColumn = supplementaryDataFrame.Columns[supplemetaryJoinColumnNames[colNameIndex]];
//Find occurrenses on current step (join column)
var newOccurrences = shrinkedRetainedColumn.GetGroupedOccurrences(supplementaryColumn, out HashSet <long> supplementaryColumnNullIndices);
//Convert indices from in key from local (shrinked row) to indices in original dataframe
if (retainedIndicesReverseMapping != null)
{
newOccurrences = newOccurrences.ToDictionary(kvp => retainedIndicesReverseMapping[kvp.Key], kvp => kvp.Value);
}
supplementaryJoinColumnsNullIndices.UnionWith(supplementaryColumnNullIndices);
// shrink join result on current column by previous join columns (if any)
// (we have to remove occurrences that doesn't exist in previous columns, because JOIN happens only if ALL left and right columns in JOIN are matched)
if (occurrences != null)
{
var shrinkedOccurences = new Dictionary <long, ICollection <long> >();
foreach (var kvp in newOccurrences)
{
var newValue = kvp.Value.Where(i => occurrences[kvp.Key].Contains(i)).ToArray();
if (newValue.Any())
{
shrinkedOccurences.Add(kvp.Key, newValue);
}
}
newOccurrences = shrinkedOccurences;
}
occurrences = newOccurrences;
}
retainedRowIndices = new Int64DataFrameColumn("RetainedIndices");
supplementaryRowIndices = new Int64DataFrameColumn("SupplementaryIndices");
//Perform Merging
var retainJoinColumns = retainedJoinColumnNames.Select(name => retainedDataFrame.Columns[name]).ToArray();
for (long i = 0; i < retainedDataFrame.Columns.RowCount; i++)
{
if (!IsAnyNullValueInColumns(retainJoinColumns, i))
{
//Get all row indexes from supplementary dataframe that sutisfy JOIN condition
if (occurrences.TryGetValue(i, out ICollection <long> rowIndices))
{
foreach (long supplementaryRowIndex in rowIndices)
{
retainedRowIndices.Append(i);
supplementaryRowIndices.Append(supplementaryRowIndex);
//store intersection if required
if (calculateIntersection)
{
if (!intersection.Contains(supplementaryRowIndex))
{
intersection.Add(supplementaryRowIndex);
}
}
}
}
else
{
if (isInner)
{
continue;
}
retainedRowIndices.Append(i);
supplementaryRowIndices.Append(null);
}
}
else
{
foreach (long row in supplementaryJoinColumnsNullIndices)
{
retainedRowIndices.Append(i);
supplementaryRowIndices.Append(row);
}
}
}
return(intersection);
}
/// <summary>
/// Wraps a <see cref="DataFrame"/> around an Arrow <see cref="RecordBatch"/> without copying data
/// </summary>
/// <param name="recordBatch"></param>
/// <returns><see cref="DataFrame"/></returns>
public static DataFrame FromArrowRecordBatch(RecordBatch recordBatch)
{
DataFrame ret = new DataFrame();
Apache.Arrow.Schema arrowSchema = recordBatch.Schema;
int fieldIndex = 0;
IEnumerable <IArrowArray> arrowArrays = recordBatch.Arrays;
foreach (IArrowArray arrowArray in arrowArrays)
{
Field field = arrowSchema.GetFieldByIndex(fieldIndex);
IArrowType fieldType = field.DataType;
DataFrameColumn dataFrameColumn = null;
switch (fieldType.TypeId)
{
case ArrowTypeId.Boolean:
BooleanArray arrowBooleanArray = (BooleanArray)arrowArray;
ReadOnlyMemory <byte> valueBuffer = arrowBooleanArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> nullBitMapBuffer = arrowBooleanArray.NullBitmapBuffer.Memory;
dataFrameColumn = new BooleanDataFrameColumn(field.Name, valueBuffer, nullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Double:
PrimitiveArray <double> arrowDoubleArray = (PrimitiveArray <double>)arrowArray;
ReadOnlyMemory <byte> doubleValueBuffer = arrowDoubleArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> doubleNullBitMapBuffer = arrowDoubleArray.NullBitmapBuffer.Memory;
dataFrameColumn = new DoubleDataFrameColumn(field.Name, doubleValueBuffer, doubleNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Float:
PrimitiveArray <float> arrowFloatArray = (PrimitiveArray <float>)arrowArray;
ReadOnlyMemory <byte> floatValueBuffer = arrowFloatArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> floatNullBitMapBuffer = arrowFloatArray.NullBitmapBuffer.Memory;
dataFrameColumn = new SingleDataFrameColumn(field.Name, floatValueBuffer, floatNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Int8:
PrimitiveArray <sbyte> arrowsbyteArray = (PrimitiveArray <sbyte>)arrowArray;
ReadOnlyMemory <byte> sbyteValueBuffer = arrowsbyteArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> sbyteNullBitMapBuffer = arrowsbyteArray.NullBitmapBuffer.Memory;
dataFrameColumn = new SByteDataFrameColumn(field.Name, sbyteValueBuffer, sbyteNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Int16:
PrimitiveArray <short> arrowshortArray = (PrimitiveArray <short>)arrowArray;
ReadOnlyMemory <byte> shortValueBuffer = arrowshortArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> shortNullBitMapBuffer = arrowshortArray.NullBitmapBuffer.Memory;
dataFrameColumn = new Int16DataFrameColumn(field.Name, shortValueBuffer, shortNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Int32:
PrimitiveArray <int> arrowIntArray = (PrimitiveArray <int>)arrowArray;
ReadOnlyMemory <byte> intValueBuffer = arrowIntArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> intNullBitMapBuffer = arrowIntArray.NullBitmapBuffer.Memory;
dataFrameColumn = new Int32DataFrameColumn(field.Name, intValueBuffer, intNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Int64:
PrimitiveArray <long> arrowLongArray = (PrimitiveArray <long>)arrowArray;
ReadOnlyMemory <byte> longValueBuffer = arrowLongArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> longNullBitMapBuffer = arrowLongArray.NullBitmapBuffer.Memory;
dataFrameColumn = new Int64DataFrameColumn(field.Name, longValueBuffer, longNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.String:
StringArray stringArray = (StringArray)arrowArray;
ReadOnlyMemory <byte> dataMemory = stringArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> offsetsMemory = stringArray.ValueOffsetsBuffer.Memory;
ReadOnlyMemory <byte> nullMemory = stringArray.NullBitmapBuffer.Memory;
dataFrameColumn = new ArrowStringDataFrameColumn(field.Name, dataMemory, offsetsMemory, nullMemory, stringArray.Length, stringArray.NullCount);
break;
case ArrowTypeId.UInt8:
PrimitiveArray <byte> arrowbyteArray = (PrimitiveArray <byte>)arrowArray;
ReadOnlyMemory <byte> byteValueBuffer = arrowbyteArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> byteNullBitMapBuffer = arrowbyteArray.NullBitmapBuffer.Memory;
dataFrameColumn = new ByteDataFrameColumn(field.Name, byteValueBuffer, byteNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.UInt16:
PrimitiveArray <ushort> arrowUshortArray = (PrimitiveArray <ushort>)arrowArray;
ReadOnlyMemory <byte> ushortValueBuffer = arrowUshortArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> ushortNullBitMapBuffer = arrowUshortArray.NullBitmapBuffer.Memory;
dataFrameColumn = new UInt16DataFrameColumn(field.Name, ushortValueBuffer, ushortNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.UInt32:
PrimitiveArray <uint> arrowUintArray = (PrimitiveArray <uint>)arrowArray;
ReadOnlyMemory <byte> uintValueBuffer = arrowUintArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> uintNullBitMapBuffer = arrowUintArray.NullBitmapBuffer.Memory;
dataFrameColumn = new UInt32DataFrameColumn(field.Name, uintValueBuffer, uintNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.UInt64:
PrimitiveArray <ulong> arrowUlongArray = (PrimitiveArray <ulong>)arrowArray;
ReadOnlyMemory <byte> ulongValueBuffer = arrowUlongArray.ValueBuffer.Memory;
ReadOnlyMemory <byte> ulongNullBitMapBuffer = arrowUlongArray.NullBitmapBuffer.Memory;
dataFrameColumn = new UInt64DataFrameColumn(field.Name, ulongValueBuffer, ulongNullBitMapBuffer, arrowArray.Length, arrowArray.NullCount);
break;
case ArrowTypeId.Decimal:
case ArrowTypeId.Binary:
case ArrowTypeId.Date32:
case ArrowTypeId.Date64:
case ArrowTypeId.Dictionary:
case ArrowTypeId.FixedSizedBinary:
case ArrowTypeId.HalfFloat:
case ArrowTypeId.Interval:
case ArrowTypeId.List:
case ArrowTypeId.Map:
case ArrowTypeId.Null:
case ArrowTypeId.Struct:
case ArrowTypeId.Time32:
case ArrowTypeId.Time64:
default:
throw new NotImplementedException(nameof(fieldType.Name));
}
ret.Columns.Insert(ret.Columns.Count, dataFrameColumn);
fieldIndex++;
}
return(ret);
}
private static Dictionary <long, ICollection <long> > GetOccurences(DataFrame retainedDataFrame, DataFrame supplementaryDataFrame,
string[] retainedJoinColumnNames, string[] supplemetaryJoinColumnNames, out HashSet <long> supplementaryJoinColumnsNullIndices)
{
supplementaryJoinColumnsNullIndices = new HashSet <long>();
// Get occurrences of values in columns used for join in the retained and supplementary dataframes
Dictionary <long, ICollection <long> > occurrences = null;
Dictionary <long, long> retainedIndicesReverseMapping = null;
for (int colNameIndex = 0; colNameIndex < retainedJoinColumnNames.Length; colNameIndex++)
{
DataFrameColumn shrinkedRetainedColumn = retainedDataFrame.Columns[retainedJoinColumnNames[colNameIndex]];
// Shrink retained column by row occurrences from previous step
if (occurrences != null)
{
// Only rows with occurences from previose step should go for futher processing
var shrinkedRetainedIndices = occurrences.Keys.ToArray();
// Create reverse mapping of index of the row in the shrinked column to the index of this row in the original dataframe (new index -> original index)
var newRetainedIndicesReverseMapping = new Dictionary <long, long>(shrinkedRetainedIndices.Length);
for (int i = 0; i < shrinkedRetainedIndices.Length; i++)
{
// Store reverse mapping to restore original dataframe indices from indices in shrinked row
var originalIndex = shrinkedRetainedIndices[i];
newRetainedIndicesReverseMapping.Add(i, originalIndex);
}
retainedIndicesReverseMapping = newRetainedIndicesReverseMapping;
var indices = new Int64DataFrameColumn("Indices", shrinkedRetainedIndices);
shrinkedRetainedColumn = shrinkedRetainedColumn.Clone(indices);
}
DataFrameColumn supplementaryColumn = supplementaryDataFrame.Columns[supplemetaryJoinColumnNames[colNameIndex]];
// Find occurrenses on current step (join column)
var newOccurrences = shrinkedRetainedColumn.GetGroupedOccurrences(supplementaryColumn, out HashSet <long> supplementaryColumnNullIndices);
// Convert indices from in key from local (shrinked row) to indices in original dataframe
if (retainedIndicesReverseMapping != null)
{
newOccurrences = newOccurrences.ToDictionary(kvp => retainedIndicesReverseMapping[kvp.Key], kvp => kvp.Value);
}
supplementaryJoinColumnsNullIndices.UnionWith(supplementaryColumnNullIndices);
// Shrink join result on current column by previous join columns (if any)
// (we have to remove occurrences that doesn't exist in previous columns, because JOIN happens only if ALL left and right columns in JOIN are matched)
if (occurrences != null)
{
newOccurrences = GetShrinkedOccurences(occurrences, newOccurrences);
}
occurrences = newOccurrences;
}
return(occurrences);
}
// TODO: Merge API with an "On" parameter that merges on a column common to 2 dataframes
/// <summary>
/// Merge DataFrames with a database style join
/// </summary>
/// <param name="other"></param>
/// <param name="leftJoinColumn"></param>
/// <param name="rightJoinColumn"></param>
/// <param name="leftSuffix"></param>
/// <param name="rightSuffix"></param>
/// <param name="joinAlgorithm"></param>
/// <returns></returns>
public DataFrame Merge <TKey>(DataFrame other, string leftJoinColumn, string rightJoinColumn, string leftSuffix = "_left", string rightSuffix = "_right", JoinAlgorithm joinAlgorithm = JoinAlgorithm.Left)
{
// A simple hash join
DataFrame ret = new DataFrame();
DataFrame leftDataFrame = this;
DataFrame rightDataFrame = other;
// The final table size is not known until runtime
long rowNumber = 0;
PrimitiveDataFrameColumn <long> leftRowIndices = new PrimitiveDataFrameColumn <long>("LeftIndices");
PrimitiveDataFrameColumn <long> rightRowIndices = new PrimitiveDataFrameColumn <long>("RightIndices");
if (joinAlgorithm == JoinAlgorithm.Left)
{
// First hash other dataframe on the rightJoinColumn
DataFrameColumn otherColumn = other.Columns[rightJoinColumn];
Dictionary <TKey, ICollection <long> > multimap = otherColumn.GroupColumnValues <TKey>(out HashSet <long> otherColumnNullIndices);
// Go over the records in this dataframe and match with the dictionary
DataFrameColumn thisColumn = Columns[leftJoinColumn];
for (long i = 0; i < thisColumn.Length; i++)
{
var thisColumnValue = thisColumn[i];
if (thisColumnValue != null)
{
if (multimap.TryGetValue((TKey)thisColumnValue, out ICollection <long> rowNumbers))
{
foreach (long row in rowNumbers)
{
leftRowIndices.Append(i);
rightRowIndices.Append(row);
}
}
else
{
leftRowIndices.Append(i);
rightRowIndices.Append(null);
}
}
else
{
foreach (long row in otherColumnNullIndices)
{
leftRowIndices.Append(i);
rightRowIndices.Append(row);
}
}
}
}
else if (joinAlgorithm == JoinAlgorithm.Right)
{
DataFrameColumn thisColumn = Columns[leftJoinColumn];
Dictionary <TKey, ICollection <long> > multimap = thisColumn.GroupColumnValues <TKey>(out HashSet <long> thisColumnNullIndices);
DataFrameColumn otherColumn = other.Columns[rightJoinColumn];
for (long i = 0; i < otherColumn.Length; i++)
{
var otherColumnValue = otherColumn[i];
if (otherColumnValue != null)
{
if (multimap.TryGetValue((TKey)otherColumnValue, out ICollection <long> rowNumbers))
{
foreach (long row in rowNumbers)
{
leftRowIndices.Append(row);
rightRowIndices.Append(i);
}
}
else
{
leftRowIndices.Append(null);
rightRowIndices.Append(i);
}
}
else
{
foreach (long thisColumnNullIndex in thisColumnNullIndices)
{
leftRowIndices.Append(thisColumnNullIndex);
rightRowIndices.Append(i);
}
}
}
}
else if (joinAlgorithm == JoinAlgorithm.Inner)
{
// Hash the column with the smaller RowCount
long leftRowCount = Rows.Count;
long rightRowCount = other.Rows.Count;
bool leftColumnIsSmaller = leftRowCount <= rightRowCount;
DataFrameColumn hashColumn = leftColumnIsSmaller ? Columns[leftJoinColumn] : other.Columns[rightJoinColumn];
DataFrameColumn otherColumn = ReferenceEquals(hashColumn, Columns[leftJoinColumn]) ? other.Columns[rightJoinColumn] : Columns[leftJoinColumn];
Dictionary <TKey, ICollection <long> > multimap = hashColumn.GroupColumnValues <TKey>(out HashSet <long> smallerDataFrameColumnNullIndices);
for (long i = 0; i < otherColumn.Length; i++)
{
var otherColumnValue = otherColumn[i];
if (otherColumnValue != null)
{
if (multimap.TryGetValue((TKey)otherColumnValue, out ICollection <long> rowNumbers))
{
foreach (long row in rowNumbers)
{
leftRowIndices.Append(leftColumnIsSmaller ? row : i);
rightRowIndices.Append(leftColumnIsSmaller ? i : row);
}
}
}
else
{
foreach (long nullIndex in smallerDataFrameColumnNullIndices)
{
leftRowIndices.Append(leftColumnIsSmaller ? nullIndex : i);
rightRowIndices.Append(leftColumnIsSmaller ? i : nullIndex);
}
}
}
}
else if (joinAlgorithm == JoinAlgorithm.FullOuter)
{
DataFrameColumn otherColumn = other.Columns[rightJoinColumn];
Dictionary <TKey, ICollection <long> > multimap = otherColumn.GroupColumnValues <TKey>(out HashSet <long> otherColumnNullIndices);
Dictionary <TKey, long> intersection = new Dictionary <TKey, long>(EqualityComparer <TKey> .Default);
// Go over the records in this dataframe and match with the dictionary
DataFrameColumn thisColumn = Columns[leftJoinColumn];
Int64DataFrameColumn thisColumnNullIndices = new Int64DataFrameColumn("ThisColumnNullIndices");
for (long i = 0; i < thisColumn.Length; i++)
{
var thisColumnValue = thisColumn[i];
if (thisColumnValue != null)
{
if (multimap.TryGetValue((TKey)thisColumnValue, out ICollection <long> rowNumbers))
{
foreach (long row in rowNumbers)
{
leftRowIndices.Append(i);
rightRowIndices.Append(row);
if (!intersection.ContainsKey((TKey)thisColumnValue))
{
intersection.Add((TKey)thisColumnValue, rowNumber);
}
}
}
else
{
leftRowIndices.Append(i);
rightRowIndices.Append(null);
}
}
else
{
thisColumnNullIndices.Append(i);
}
}
for (long i = 0; i < otherColumn.Length; i++)
{
var value = otherColumn[i];
if (value != null)
{
if (!intersection.ContainsKey((TKey)value))
{
leftRowIndices.Append(null);
rightRowIndices.Append(i);
}
}
}
// Now handle the null rows
foreach (long?thisColumnNullIndex in thisColumnNullIndices)
{
foreach (long otherColumnNullIndex in otherColumnNullIndices)
{
leftRowIndices.Append(thisColumnNullIndex.Value);
rightRowIndices.Append(otherColumnNullIndex);
}
if (otherColumnNullIndices.Count == 0)
{
leftRowIndices.Append(thisColumnNullIndex.Value);
rightRowIndices.Append(null);
}
}
if (thisColumnNullIndices.Length == 0)
{
foreach (long otherColumnNullIndex in otherColumnNullIndices)
{
leftRowIndices.Append(null);
rightRowIndices.Append(otherColumnNullIndex);
}
}
}
else
{
throw new NotImplementedException(nameof(joinAlgorithm));
}
for (int i = 0; i < leftDataFrame.Columns.Count; i++)
{
ret.Columns.Insert(i, leftDataFrame.Columns[i].Clone(leftRowIndices));
}
for (int i = 0; i < rightDataFrame.Columns.Count; i++)
{
DataFrameColumn column = rightDataFrame.Columns[i].Clone(rightRowIndices);
SetSuffixForDuplicatedColumnNames(ret, column, leftSuffix, rightSuffix);
ret.Columns.Insert(ret.Columns.Count, column);
}
return(ret);
}
