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quantconnect--lean/Common/Python/PandasConverter.DataFrameGenerator.cs
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2026-07-13 13:02:50 +08:00

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C#

/*
* QUANTCONNECT.COM - Democratizing Finance, Empowering Individuals.
* Lean Algorithmic Trading Engine v2.0. Copyright 2014 QuantConnect Corporation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using Python.Runtime;
using QuantConnect.Data;
using QuantConnect.Data.Market;
using QuantConnect.Data.UniverseSelection;
using QuantConnect.Util;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
namespace QuantConnect.Python
{
public partial class PandasConverter
{
/// <summary>
/// Helper class to generate data frames from slices
/// </summary>
private class DataFrameGenerator
{
private static readonly string[] MultiBaseDataCollectionDataFrameNames = new[] { "collection_symbol", "time" };
private static readonly string[] MultiCanonicalSymbolsDataFrameNames = new[] { "canonical", "time" };
private static readonly string[] SingleBaseDataCollectionDataFrameNames = new[] { "time" };
private readonly Type _dataType;
private readonly bool _requestedTick;
private readonly bool _requestedQuoteBar;
private readonly bool _requestedTradeBar;
private readonly bool _timeAsColumn;
/// <summary>
/// PandasData instances for each symbol. Does not hold BaseDataCollection instances.
/// </summary>
private Dictionary<Symbol, PandasData> _pandasData;
private List<(Symbol Symbol, DateTime Time, IEnumerable<ISymbolProvider> Data)> _collections;
private int _maxLevels;
private bool _shouldUseSymbolOnlyIndex;
private readonly bool _flatten;
protected DataFrameGenerator(Type dataType = null, bool timeAsColumn = false, bool flatten = false)
{
_dataType = dataType;
// if no data type is requested we check all
_requestedTick = dataType == null || dataType == typeof(Tick) || dataType == typeof(OpenInterest);
_requestedTradeBar = dataType == null || dataType == typeof(TradeBar);
_requestedQuoteBar = dataType == null || dataType == typeof(QuoteBar);
_timeAsColumn = timeAsColumn;
_flatten = flatten;
}
public DataFrameGenerator(IEnumerable<Slice> slices, bool flatten = false, Type dataType = null)
: this(dataType, flatten: flatten)
{
AddData(slices);
}
/// <summary>
/// Extracts the data from the slices and prepares it for DataFrame generation.
/// If the slices contain BaseDataCollection instances, they are added to the collections list for proper handling.
/// For the rest of the data, PandasData instances are created for each symbol and the data is added to them for later processing.
/// </summary>
protected void AddData(IEnumerable<Slice> slices)
{
HashSet<SecurityIdentifier> addedData = null;
foreach (var slice in slices)
{
foreach (var data in slice.AllData)
{
if (_flatten && IsCollection(data.GetType()))
{
AddCollection(data.Symbol, data.EndTime, (data as IEnumerable).Cast<ISymbolProvider>());
continue;
}
var pandasData = GetPandasData(data);
if (pandasData.IsCustomData || (_requestedTick && data is Tick))
{
pandasData.Add(data);
}
else
{
if (!_requestedTradeBar && !_requestedQuoteBar && _dataType != null && data.GetType().IsAssignableTo(_dataType))
{
// support for auxiliary data history requests
pandasData.Add(data);
continue;
}
// we add both quote and trade bars for each symbol at the same time, because they share the row in the data frame else it will generate 2 rows per series
if (_requestedTradeBar && _requestedQuoteBar)
{
addedData ??= new();
if (!addedData.Add(data.Symbol.ID))
{
continue;
}
}
// the slice already has the data organized by symbol so let's take advantage of it using Bars/QuoteBars collections
QuoteBar quoteBar;
var tradeBar = _requestedTradeBar ? data as TradeBar : null;
if (tradeBar != null)
{
slice.QuoteBars.TryGetValue(tradeBar.Symbol, out quoteBar);
}
else
{
quoteBar = _requestedQuoteBar ? data as QuoteBar : null;
if (quoteBar != null)
{
slice.Bars.TryGetValue(quoteBar.Symbol, out tradeBar);
}
}
pandasData.Add(tradeBar, quoteBar);
}
}
addedData?.Clear();
}
}
/// <summary>
/// Adds a collection of data and prepares it for DataFrame generation.
/// If the collection holds BaseDataCollection instances, they are added to the collections list for proper handling.
/// For the rest of the data, PandasData instances are created for each symbol and the data is added to them for later processing.
/// </summary>
protected void AddData<T>(IEnumerable<T> data)
where T : ISymbolProvider
{
var type = typeof(T);
var isCollection = IsCollection(type);
if (_flatten && isCollection)
{
foreach (var collection in data)
{
var baseData = collection as BaseData;
var collectionData = collection as IEnumerable;
AddCollection(baseData.Symbol, baseData.EndTime, collectionData.Cast<ISymbolProvider>());
}
}
else
{
Symbol prevSymbol = null;
PandasData prevPandasData = null;
foreach (var item in data)
{
var pandasData = prevSymbol != null && item.Symbol == prevSymbol ? prevPandasData : GetPandasData(item);
pandasData.Add(item);
prevSymbol = item.Symbol;
prevPandasData = pandasData;
}
// Multiple symbols detected, use symbol only indexing for performance reasons
if (_pandasData != null && _pandasData.Count > 1)
{
_shouldUseSymbolOnlyIndex = true;
}
}
}
/// <summary>
/// Generates the data frame
/// </summary>
/// <param name="levels">The number of level the index should have. If not provided, it will be inferred from the data</param>
/// <param name="sort">Whether to sort the data frames on concatenation</param>
/// <param name="filterMissingValueColumns">Whether to filter missing values. See <see cref="PandasData.ToPandasDataFrame(int, bool)"/></param>
/// <param name="symbolOnlyIndex">Whether to assume the data has multiple symbols and also one data point per symbol.
/// This is used for performance purposes</param>
/// <param name="forceMultiValueSymbol">Useful when the data contains points for multiple symbols.
/// If false and <paramref name="symbolOnlyIndex"/> is true, it will assume there is a single point for each symbol,
/// and will apply performance improvements for the data frame generation.</param>
public PyObject GenerateDataFrame(int? levels = null, bool sort = true, bool filterMissingValueColumns = true,
bool symbolOnlyIndex = false, bool forceMultiValueSymbol = false)
{
using var _ = Py.GIL();
var pandasDataDataFrames = GetPandasDataDataFrames(levels, filterMissingValueColumns, symbolOnlyIndex, forceMultiValueSymbol).ToList();
var collectionsDataFrames = GetCollectionsDataFrames(symbolOnlyIndex, forceMultiValueSymbol).ToList();
try
{
if (collectionsDataFrames.Count == 0)
{
return ConcatDataFrames(pandasDataDataFrames, sort, dropna: true);
}
var dataFrames = collectionsDataFrames.Select(x => x.Item3).Concat(pandasDataDataFrames);
if (symbolOnlyIndex)
{
return ConcatDataFrames(dataFrames, sort, dropna: true);
}
else if (_collections.DistinctBy(x => x.Symbol).Count() > 1)
{
var keys = collectionsDataFrames
.Select(x => new object[] { x.Item1, x.Item2 })
.Concat(pandasDataDataFrames.Select(x => new object[] { x, DateTime.MinValue }));
var names = _collections.Any(x => x.Symbol.IsCanonical())
? MultiCanonicalSymbolsDataFrameNames
: MultiBaseDataCollectionDataFrameNames;
return ConcatDataFrames(dataFrames, keys, names, sort, dropna: true);
}
else
{
var keys = collectionsDataFrames
.Select(x => new object[] { x.Item2 })
.Concat(pandasDataDataFrames.Select(x => new object[] { DateTime.MinValue }));
return ConcatDataFrames(dataFrames, keys, SingleBaseDataCollectionDataFrameNames, sort, dropna: true);
}
}
finally
{
foreach (var df in pandasDataDataFrames.Concat(collectionsDataFrames.Select(x => x.Item3)))
{
df.Dispose();
}
}
}
/// <summary>
/// Creates the data frames for the data stored in the <see cref="_pandasData"/> dictionary
/// </summary>
private IEnumerable<PyObject> GetPandasDataDataFrames(int? levels, bool filterMissingValueColumns, bool symbolOnlyIndex, bool forceMultiValueSymbol)
{
if (_pandasData is null || _pandasData.Count == 0)
{
yield break;
}
if (!forceMultiValueSymbol && (symbolOnlyIndex || _shouldUseSymbolOnlyIndex))
{
yield return PandasData.ToPandasDataFrame(_pandasData.Values, skipTimesColumn: true);
yield break;
}
foreach (var data in _pandasData.Values)
{
yield return data.ToPandasDataFrame(levels ?? _maxLevels, filterMissingValueColumns);
}
}
/// <summary>
/// Generates the data frames for the base data collections
/// </summary>
private IEnumerable<(Symbol, DateTime, PyObject)> GetCollectionsDataFrames(bool symbolOnlyIndex, bool forceMultiValueSymbol)
{
if (_collections is null || _collections.Count == 0)
{
yield break;
}
foreach (var (symbol, time, data) in _collections.GroupBy(x => x.Symbol).SelectMany(x => x))
{
var generator = new DataFrameGenerator(_dataType, timeAsColumn: !symbolOnlyIndex, flatten: _flatten);
generator.AddData(data);
var dataFrame = generator.GenerateDataFrame(symbolOnlyIndex: symbolOnlyIndex, forceMultiValueSymbol: forceMultiValueSymbol);
yield return (symbol, time, dataFrame);
}
}
private PandasData GetPandasData(ISymbolProvider data)
{
_pandasData ??= new();
if (!_pandasData.TryGetValue(data.Symbol, out var pandasData))
{
pandasData = new PandasData(data, _timeAsColumn);
_pandasData[data.Symbol] = pandasData;
_maxLevels = Math.Max(_maxLevels, pandasData.Levels);
}
return pandasData;
}
private void AddCollection(Symbol symbol, DateTime time, IEnumerable<ISymbolProvider> data)
{
_collections ??= new();
_collections.Add((symbol, time, data));
}
/// <summary>
/// Determines whether the type is considered a collection for flattening.
/// Any object that is a <see cref="BaseData"/> and implements <see cref="IEnumerable{ISymbolProvider}"/>
/// is considered a base data collection.
/// This allows detecting collections of cases like <see cref="OptionUniverse"/> (which is a direct subclass of
/// <see cref="BaseDataCollection"/>) and <see cref="OptionChain"/>, which is a collection of <see cref="OptionContract"/>
/// </summary>
private static bool IsCollection(Type type)
{
return type.IsAssignableTo(typeof(BaseData)) &&
type.GetInterfaces().Any(x => x.IsGenericType &&
x.GetGenericTypeDefinition().IsAssignableTo(typeof(IEnumerable<>)) &&
x.GenericTypeArguments[0].IsAssignableTo(typeof(ISymbolProvider)));
}
}
private class DataFrameGenerator<T> : DataFrameGenerator
where T : ISymbolProvider
{
public DataFrameGenerator(IEnumerable<T> data, bool flatten)
: base(flatten: flatten)
{
AddData(data);
}
}
}
}