Elder-ray Index

get_elder_ray(quotes, lookback_periods=13)


name type notes
quotes Iterable[Quote] Iterable of the Quote class or its sub-class.
See here for usage with pandas.DataFrame
lookback_periods int, default 13 Number of periods (N) for the underlying EMA evaluation. Must be greater than 0.

Historical quotes requirements

You must have at least 2×N or N+100 periods of quotes, whichever is more, to cover the convergence periods. Since this uses a smoothing technique, we recommend you use at least N+250 data points prior to the intended usage date for better precision.

quotes is an Iterable[Quote] collection of historical price quotes. It should have a consistent frequency (day, hour, minute, etc). See the Guide for more information.



Convergence warning: The first N+100 periods will have decreasing magnitude, convergence-related precision errors that can be as high as ~5% deviation in indicator values for earlier periods.


name type notes
date datetime Date
ema float, Optional Exponential moving average of Close price
bull_power float, Optional Bull Power
bear_power float, Optional Bear Power


See Utilities and Helpers for more information.


from stock_indicators import indicators

# This method is NOT a part of the library.
quotes = get_historical_quotes("SPY")

# calculate ElderRay(13)
results = indicators.get_elder_ray(quotes, 13)

About Elder-ray Index

Created by Alexander Elder, the Elder-ray Index, also known as Bull and Bear Power, depicts buying and selling pressure. [Discuss] 💬