Signal Line

Problem

Compute the MACD signal line: build the MACD series from the short and long EMAs, then apply an EMA with span signal_span to that series and return its final value. Each EMA uses smoothing factor 2 / (span + 1) and starts at the first value of its input.

Return 0.0 for an empty series.

Hint

Signal-line crossings are the classic MACD trigger events.

Test cases

case 1

in: [[1,2,3,4,5],2,3,2]

expected: 0.4099794238683124

case 2

in: [[5,5,5],12,26,9]

expected: 0

case 3

in: [[10],3,5,2]

expected: 0

case 4

in: [[10,9,8,7,6],2,4,3]

expected: -0.6606271604938272

Starter codePython

def signal_line(prices, short_span, long_span, signal_span):
    # Your code here
    pass

4 test cases · run your code against them in the editor