The method of displaying a two-dimensional matrix including a matrix diagram of correlation coefficients in the form of a heat map, currently found two:

The first is to use the functions of the pandas package, but the visual inspection of the pandas package cannot display the numbers?

If you want to try it, you can refer to https://zhuanlan.zhihu.com/p/26100511

So I studied the second method, which is to draw with seaborn package.

Reference

https://blog.csdn.net/a19990412/article/details/79304944

 https://blog.csdn.net/sunchengquan/article/details/78573244

https://blog.csdn.net/weixin_39541558/article/details/79813936

Wait for the article, the parameters in sns.heatmap below can refer to the article in the first link. Can alsosns.heatmap?Inquire.

In the following sns.heatmap, annot means that we want to display the numbers in the array, because we want to display the numbers, so it is round. If you want to represent the correlation matrix, it is recommended to multiply by 10, round, then you will get -10 to 10 The figures between, look better. You can set the maximum and minimum values ​​of the numbers in the array, or you can use the center=0 setting, depending on your understanding of the numbers in the array. If you need to display xticklabels and yticklabels, you need to set the parameter to True. The meaning of square is that each cell is a square, otherwise it is a matrix, and then finally cmap is the color of the graph. You can use the one below, as well as "Blues" and so on. You can also set the line width of which cells are divided, etc., you can query through sns.heatmap?.

import seaborn as sns
import numpy as np
import pandas as pd
a = np.random.rand(4,3)
fig, ax = plt.subplots(figsize = (9,9))
#The heat map of the two-dimensional array, if the tick labels of the horizontal axis and the number axis should be added, you can convert the array into a column
 The DataFrame of # and index are directly drawn and generated, and can be added later. If you add it later, it is more flexible, including setting the size direction of labels.
sns.heatmap(pd.DataFrame(np.round(a,2), columns = ['a', 'b', 'c'], index = range(1,5)), 
                annot=True, vmax=1,vmin = 0, xticklabels= True, yticklabels= True, square=True, cmap="YlGnBu")
#sns.heatmap(np.round(a,2), annot=True, vmax=1,vmin = 0, xticklabels= True, yticklabels= True, 
#            square=True, cmap="YlGnBu")
 ax.set_title('Two-dimensional array heat map', fontsize = 18)
 ax.set_ylabel('number', fontsize = 18)
 ax.set_xlabel(' Letter', fontsize = 18) #The horizontal direction becomes the y-axis, which is the same as the original layout of the matrix

ax.set_yticklabels(['One','Two','Three'], fontsize = 18, rotation = 360, horizontalalignment='right')
ax.set_xticklabels(['a', 'b', 'c'], fontsize = 18, horizontalalignment='right')

After the article is published, it cannot be modified anymore, which is really annoying.