python - matplotlib graph fill 2 colors above and below axis -

i have line graph partly above , below x-axis of 0. how can color area above line green, , below red? here's code:

hydropathy_dict = {"i":-0.528,          "l":-0.342,         "f":-0.370,         "v":-0.308,         "m":-0.324,         "p":-0.322,         "w": -0.270,         "h": 2.029,         "t": 0.853,         "e": 3.173,         "q": 2.176,         "c": 0.081,         "y": 1.677,         "a":-0.495,         "s": 0.936,         "n": 2.354,         "d": 9.573,         "r": 4.383,         "g": 0.386,         "k": 2.101         }     seq = 'chcrrscysteysygtctvmginhrfcc'     hydropathy_list = []     plot_x_axis = []     aa in seq:         hydropathy_list.append(hydropathy_dict[aa])     print(acc,hydropathy_list)     in range(len(hydropathy_list)):         plot_x_axis.append(i)      plt.plot(plot_x_axis,hydropathy_list)     plt.plot([0,len(hydropathy_list)],[0,0])     plt.show() 

try this:

import matplotlib.pyplot plt import numpy np scipy import interpolate  hydropathy_dict = {"i":-0.528,          "l":-0.342,         "f":-0.370,         "v":-0.308,         "m":-0.324,         "p":-0.322,         "w": -0.270,         "h": 2.029,         "t": 0.853,         "e": 3.173,         "q": 2.176,         "c": 0.081,         "y": 1.677,         "a":-0.495,         "s": 0.936,         "n": 2.354,         "d": 9.573,         "r": 4.383,         "g": 0.386,         "k": 2.101         }  seq = 'chcrrscysteysygtctvmginhrfcc' hydropathy_list = [] plot_x_axis = [] aa in seq:     hydropathy_list.append(hydropathy_dict[aa])  #print(seq, hydropathy_list) in range(len(hydropathy_list)):     plot_x_axis.append(i)  # convert np array hydropathy_list = np.array(hydropathy_list) plot_x_axis = np.array(plot_x_axis)  # densify data filled color plot f = interpolate.interp1d(plot_x_axis, hydropathy_list) xnew = np.arange(plot_x_axis[0], plot_x_axis[-1], 0.1) ynew = f(xnew)  plt.plot(plot_x_axis, hydropathy_list)       # blue line plt.plot([0, len(hydropathy_list)], [0,0])   # green line  # use xnew, ynew plot filled-color graphs plt.fill_between(xnew, 0, ynew, where=(ynew-1) < -1 , color='red') plt.fill_between(xnew, 0, ynew, where=(ynew-1) > -1 , color='green')  plt.show() 

edit

(in response of questions in comment)

statement where=(ynew-1)<-1 inside fill_between() requires ynew numpy array (simple list won't work).

scipy.interpolate() used more points along curve, that, color fills target areas completely.

with original points, result looks this: