Elder-ray Index
get_elder_ray(quotes, lookback_periods=13)
Parameters
name | type | notes |
---|---|---|
quotes |
Iterable[Quote] | Iterable(such as list or an object having __iter__() ) of the Quote class or its sub-class. • Need help 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.
Returns
ElderRayResults[ElderRayResult]
- This method returns a time series of all available indicator values for the
quotes
provided. -
ElderRayResults
is just a list ofElderRayResult
. - It always returns the same number of elements as there are in the historical quotes.
- It does not return a single incremental indicator value.
- The first
N-1
periods will haveNone
indicator values since there’s not enough data to calculate.
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.
ElderRayResult
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 |
Utilities
See Utilities and Helpers for more information.
Example
from stock_indicators import indicators
# This method is NOT a part of the library.
quotes = get_history_from_feed("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]