How to use variable quantity with ibc.placeorder function


I am using below code for sending orders TWS;

if( LastValue( Buy ) )
	ibc = GetTradingInterface("IB"); 

	// check if we are connected OK 
	if( ibc.IsConnected() ) 
		// check if we do not have already open position on this stock 
		if( ibc.GetPositionSize( Name() ) == 0 ) 
			// transmit order 
			ibc.PlaceOrder( Name(), "Buy", quantity , "MKT", 0, 0, "Day", True); 

this works if quantity is explicitly declared as a number. But I want to use variable quantity, like what is derived from below formula. Could you pls advice where am I going wrong?

thirdqty=IIf(C<SM1*.9, (firstqty+secondqty)*4,0);


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Try removing fractional shares from quantity before submitting the order using the int(), round(), ceil() or floor() functions.

I tried all these functions but no luck. If I print the value of quantity it displays 66.000. If I make quantity=66.000; it works, but the moment I change it to quantity=10000/C; it gives “COM error: Type mismatch on one or more arguments”.

Sorry I didn’t notice this earlier…

Calculating 10000/C produces an array with a result for each bar. Your other calculations also produce arrays. You need to extract a single value from the array, presumably the last one.

Try using LastValue(quantity) to place the order.


It worked, Thanks a lot Alan.