How can I create an image in python by using a matrix?

Question

m = [98.75, 97, 96.66, 42, 9, 4, 1,98.33, 95, 93.33, 44, 7, 4, 1,95,94,87.5, 38.33, 5, 0, 
0,95, 93, 85, 35.55,5,0,0,95,92,83,30,3.33,0,0,95,91,80,28,1.66,0,0,95,90,75,21.25,1.66,0,0]

From the above list, I need to create a 7x7 matrix, as follows:

      [,1]  [,2]  [,3]  [,4]  [,5]  [,6]  [,7]
 [1,] 98.75 98.33 95.00 95.00 95.00 95.00 95.00
 [2,] 97.00 95.00 94.00 93.00 92.00 91.00 90.00
 [3,] 96.66 93.33 87.50 85.00 83.00 80.00 75.00
 [4,] 42.00 44.00 38.33 35.55 30.00 28.00 21.25
 [5,]  9.00  7.00  5.00  5.00  3.33  1.66  1.66
 [6,]  4.00  4.00  0.00  0.00  0.00  0.00  0.00
 [7,]  1.00  1.00  0.00  0.00  0.00  0.00  0.00

from the matrix need to generate an image like:

What have you tried? Where is the difficulty? Surely you don’t expect a stranger to do all your work for you, right? — Cris Luengo
– Cris Luengo, Commented Jun 21, 2020 at 14:58

My Work · Accepted Answer · 2020-06-21 15:16:45Z

3

First, convert list to array with numpy, then reshape and then use your favourite package to plot, eg. seaborn or matplotlib:

import numpy as np
import seaborn as sns
import matplotlib.pyplot as plt

m = [98.75, 97, 96.66, 42, 9, 4, 1,98.33, 95, 93.33, 44, 7, 4, 1,95,94,87.5, 38.33, 5, 0, 
0,95, 93, 85, 35.55,5,0,0,95,92,83,30,3.33,0,0,95,91,80,28,1.66,0,0,95,90,75,21.25,1.66,0,0]


data = np.asarray(m).reshape(7,7)[::-1]
sns.heatmap(data, cmap = 'jet')
# plt.imshow(data)
plt.xlabel('Gain USRP2 (receiver side) (db)')
plt.ylabel('Gain USRP1 (sender side) (db)')

edited Jun 21, 2020 at 15:16

answered Jun 21, 2020 at 15:00

My Work

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4 Comments

Nicolas Gervais Over a year ago

Reshaping like this yields an array different than what OP showed

My Work Over a year ago

@Angry Bird, what is the correct answer? The one you plot or the one you have in your results? If the latter, just transpose the matrix

Angry Bird Over a year ago

Thanks for your support, appreciate it!

My Work Over a year ago

If it answers your question, then accept it as an answer, if not, please, clarify what is missing or what you meant

Nicolas Gervais · Accepted Answer · 2020-06-21 15:02:52Z

2

I like to use plt.matshow():

import numpy as np
import matplotlib.pyplot as plt

m = [98.75, 97, 96.66, 42, 9, 4, 1,98.33, 95, 93.33, 
     44, 7, 4, 1,95,94,87.5, 38.33, 5, 0, 0,95, 93, 
     85, 35.55,5,0,0,95,92,83,30,3.33,0,0,95,91,80,28,
     1.66,0,0,95,90,75,21.25,1.66,0,0]

plt.matshow(np.array(m).reshape(7, 7).T)
plt.show()

answered Jun 21, 2020 at 15:02

Nicolas Gervais

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