helpers.py

import numpy as np


# The "Point-Slope Formula"
# https://www.mathsisfun.com/algebra/line-equation-2points.html
def point_slope(x1, y1, x2, y2, x):
    m = (y2 - y1) / (x2 - x1)
    x0 = y1 - (m * x1)
    return m * x + x0


# Make arrays the same lenght
# https://docs.jesse.trade/docs/indicators/custom-indicators.html#make-arrays-the-same-lenght
def same_length(bigger, shorter):
    return np.concatenate((np.full((bigger.shape[0] - shorter.shape[0]), np.nan), shorter))


# Numpy's Shift
# https://docs.jesse.trade/docs/indicators/custom-indicators.html#numpy-s-shift
def shift(arr, num, fill_value=np.nan):
    result = np.empty_like(arr)
    if num > 0:
        result[:num] = fill_value
        result[num:] = arr[:-num]
    elif num < 0:
        result[num:] = fill_value
        result[:num] = arr[-num:]
    else:
        result[:] = arr
    return result