Python-matplotlib module exercises, the use of histograms

import matplotlib.pyplot as plt 
import numpy as np 

def test4 (): 
    names = ['Movie 1', 'Movie 2', 'Movie 3'] 
    real_num1 = [7548, 4013, 1673] 
    real_num2 = [5453, 1840, 1080 ] 
    real_num3 = [4348, 2345, 1890] 
    x = np.arange (len (names)) 
    # draw a column chart 
    width = 0.3 
    plt.bar (x, real_num1, alpha = 0.5, width = width, label = names [0 ]) 
    plt.bar ([i + width for i in x], real_num2, alpha = 0.5, width = width, label = names [1]) 
    plt.bar ([i + 2 * width for i in x], real_num3 , alpha = 0.5, width = width, label = names [2]) 
    # Normal display Chinese 
    plt.rcParams ["font.sans-serif"] = ["SimHei"] 
    # Set the value of the x coordinate axis 
    x_label = ["第{}day".format(i+1) for i in x]
    # Let the x coordinate axis be displayed in the middle
    plt.xticks ([i + width for i in x], x_label) 
    # add ylabel 
    plt.ylabel ("number of box office") 
    # add legend 
    plt.legend () 
    # add title 
    plt.title ("3 days 3 movie box office Number ") 
    plt.show () 

test4 ()

 The results show that: