python plot line with error bar

我们有时候会面临画带有误差的图，大致长成下面这个样子

image.png

代码为

# -*- coding: utf-8 -*-
"""
Created on Sun Jul  5 21:12:17 2020

@author: x1c
"""

import matplotlib.pyplot as plt
import seaborn as sns
import numpy as np
sns.set()

#plt.plot(x,(y1+y2)/2,color = 'red')
#plt.fill_between(x, y1, y2, color='red', alpha=0.1)



def plot_error(x,y,label,color='gray'):
    # Input y=[y1,y2,...] yi.shape = [m,1]
    Y = np.zeros((y[0].shape[0],len(y)))
    y_mean = 0
    for i in range(len(y)):
        y_mean += y[i]
        Y[:,i] = y[i][:,0]
    #print(Y)
    y_mean /= len(y)
    y_max = np.max(Y,axis=1)
    y_min = np.min(Y,axis=1)
    #print(y_max)
    x = x.squeeze()
    y_mean = y_mean.squeeze()
    y_max = y_max.squeeze()
    y_min = y_min.squeeze()
    plt.plot(x,y_mean,label=label,color=color)
    plt.fill_between(x,y_min,y_max,color=color,alpha=0.1)
    plt.show()
    
   
x = np.arange(0,10)
y1 = x+x**2+(np.random.random(10,)-1/2)*100
y2 = x+x**2+(np.random.random(10,)-1/2)*100
x = x.reshape(-1,1)
y1 = y1.reshape(-1,1)
y2 = y2.reshape(-1,1)
plot_error(x,[y1,y2],label='test',color='gray')

稍加解读，seaborn我们只是用了一下配色，不用是没关系的，只是我觉得这种配色比较美观。
关键的一行代码是plt.fill_between，就是把阴影画出来的关键代码，alpha用来调节其透明度。