RSI needs period flexibility

[tryrt4ms]

RSI function :

Args :
    df : Pandas DataFrame which contains ['date', 'open', 'high', 'low', 'close', 'volume'] columns
    base : String indicating the column name from which the MACD needs to be computed from (Default close)
    period : Integer indicates the period of computation in terms of number of candles
    
Returns :
    df : Pandas DataFrame with new columns added for 
        Relative Strength Index (RSI_$period)
"""

delta = df[base].diff()
up, down = delta.copy(), delta.copy()
if len(delta)>(period-1):
    up[up < 0] = 0
    down[down > 0] = 0

    rUp = up.ewm(com=period - 1,  adjust=False).mean()
    rDown = down.ewm(com=period - 1, adjust=False).mean().abs()

    df['RSI_' + str(period)] = 100 - 100 / (1 + rUp / rDown)
    df['RSI_' + str(period)].fillna(0, inplace=True)
else:
    df['RSI_' + str(period)] = pd.Series()
    df['RSI_' + str(period)].fillna(0, inplace=True)

return df

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