import numpy as np
x = np.arange(0, len(y_list), 1)
y = np.array(y_list)
fit_result = np.polyfit(x, y, 3)
print(fit_result)
import matplotlib.pyplot as plt
p1d = np.poly1d(fit_result)
y_values = p1d(x) # 也可以用 yvals = np.polyval(fit_result, x)
plot1 = plt.plot(x, y, '*', label='original values')
plot2 = plt.plot(x, y_values, 'r', label='curve fit values')
plt.xlabel('x-axis')
plt.ylabel('y-axis')
plt.legend(loc=4)
plt.title('curve fitting')
plt.show()
