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pandas-ta/pandas_ta/volatility/atr.py
T
2019-05-19 14:26:34 -07:00

78 lines
2.2 KiB
Python

# -*- coding: utf-8 -*-
from .true_range import true_range
from ..utils import get_drift, get_offset, verify_series
def atr(high, low, close, length=None, mamode=None, drift=None, offset=None, **kwargs):
"""Indicator: Average True Range (ATR)"""
# Validate arguments
high = verify_series(high)
low = verify_series(low)
close = verify_series(close)
length = int(length) if length and length > 0 else 14
min_periods = int(kwargs['min_periods']) if 'min_periods' in kwargs and kwargs['min_periods'] is not None else length
mamode = mamode.lower() if mamode else 'ema'
drift = get_drift(drift)
offset = get_offset(offset)
# Calculate Result
tr = true_range(high=high, low=low, close=close, drift=drift)
if mamode == 'ema':
atr = tr.ewm(span=length, min_periods=min_periods).mean()
else:
atr = tr.rolling(length, min_periods=min_periods).mean()
# Offset
if offset != 0:
atr = atr.shift(offset)
# Handle fills
if 'fillna' in kwargs:
atr.fillna(kwargs['fillna'], inplace=True)
if 'fill_method' in kwargs:
atr.fillna(method=kwargs['fill_method'], inplace=True)
# Name and Categorize it
atr.name = f"ATR_{length}"
atr.category = 'volatility'
return atr
atr.__doc__ = \
"""Average True Range (ATR)
Averge True Range is used to measure volatility, especially
volatility caused by gaps or limit moves.
Sources:
https://www.tradingview.com/wiki/Average_True_Range_(ATR)
Calculation:
Default Inputs:
length=14, drift=1
SMA = Simple Moving Average
EMA = Exponential Moving Average
TR = True Range
tr = TR(high, low, close, drift)
if 'ema':
ATR = EMA(tr, length)
else:
ATR = SMA(tr, length)
Args:
high (pd.Series): Series of 'high's
low (pd.Series): Series of 'low's
close (pd.Series): Series of 'close's
length (int): It's period. Default: 14
mamode (str): Two options: None or 'ema'. Default: 'ema'
drift (int): The difference period. Default: 1
offset (int): How many periods to offset the result. Default: 0
Kwargs:
fillna (value, optional): pd.DataFrame.fillna(value)
fill_method (value, optional): Type of fill method
Returns:
pd.Series: New feature generated.
"""