Which language has better support? Python or C#?

Hi all,

I've been having difficulties getting some Python code running - i.e.: just getting simple History data.
On the other hand, I managed to get the "same" Python code but in C# running without issues.

Does C# have better support than Python at QuantConnect?
What about local development? I'm used to local editors for syntax, compilation checks, etc and I feel that the web IDE is not ideal, at least for me, if you want to get continuity while developing.

Looking forward to hearing about your experiences.



ps: See the code snippets below:

class HistorySpike(QCAlgorithm):

def Initialize(self):
self.SetStartDate(2018, 7, 2)
self.SetEndDate(2018, 7, 2)


self.AddEquity("SPY", Resolution.Minute)

slices = self.History(TimeSpan.FromDays(5))

if not slices.empty:
bars = slices.loc["SPY"]
close = bars["close"]

namespace QuantConnect
public class HistorySpike : QCAlgorithm
public override void Initialize()
SetStartDate(2018, 7, 2);
SetEndDate(2018, 7, 2);


AddEquity("SPY", Resolution.Minute);

IEnumerable<Slice> slices = History(TimeSpan.FromDays(5));
IEnumerable<TradeBar> bars = slices.Get("SPY");
IEnumerable<decimal> decimals = slices.Get("SPY", Field.Close);
double[] doubleArray = decimals.ToDoubleArray();


Update Backtest

QuantConnect supports both C# and Python, however, LEAN is written in C# and its local development will be easier in C# and Visual Studio. It is one of our goals to have LEAN written in Python soon.

The reason to why the self.History function did not work is because the method call above provides an enumerable slice. If we want to request pandas, the method call self.History(self.Securities.Keys, (TimeSpan.FromDays(5)) will work. Otherwise, we can do:

slices = self.History(4, Resolution.Daily)
for slice in slices:


Hi Gurumeher,

Thanks for your help. It worked!
Good to know about the goal of having LEAN written in Python.



Update Backtest


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