• Python: 3.8.11
  • Matplotlib: 3.3.4
  • OS: Ubuntu Kylin 20.04
  • Conda: 4.10.1
  • Jupyter lab: 3.1.4

 

Code sample

import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline
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# [low,high)
# Black is 0
# White is 255
# Add: The MNIST dataset is just the opposite
image = np.random.randint(low=0,high=256,size=(28.28))
image

array([[195.182.114.92.182.180.169.54.238.68.166.1.162.159.103.149.122.153.51.244.66.26.194.3.90.57.186.174],
       [212.109.154.41.149.27.141.114.191.166.127.66.52.120.8.156.160.151.145.105.37.120.241.233.28.48.133.99],
       [ 58.167.169.213.77.129.30.67.46.175.185.146.96.73.92.126.243.154.83.174.59.222.32.236.173.79.6.237],
       [185.42.64.250.146.140.23.1.163.196.76.43.129.84.119.94.69.134.147.87.241.244.33.6.9.135.195.173],
       [215.51.162.218.79.51.197.133.174.151.44.118.134.21.160.147.147.167.141.5.128.90.188.53.164.3.152.159],
       [158.26.120.12.167.68.72.156.136.97.39.141.11.179.38.140.9.179.6.20.156.177.107.131.99.36.216.216],
       [231.73.18.209.155.96.81.240.210.153.41.162.166.147.230.53.67.153.12.100.151.192.111.232.52.250.88.70],
       [167.201.39.37.131.216.44.215.119.71.118.163.233.38.177.50.237.50.200.169.32.137.96.165.68.226.253.200],
       [115.135.36.200.90.43.96.253.234.199.146.177.85.162.37.95.45.148.188.135.151.197.24.198.171.143.107.184],
       [  1.213.79.125.173.94.50.79.105.65.17.29.91.222.36.40.108.88.161.118.226.174.44.53.111.238.203.179],
       [230.140.237.73.48.71.130.4.220.153.187.198.250.111.18.171.57.128.46.100.64.98.47.60.197.9.104.101],
       [ 26.18.130.210.49.38.150.21.248.65.16.152.173.76.131.3.36.85.194.214.92.168.105.194.61.88.147.153],
       [ 87.24.215.115.244.236.33.12.218.189.157.158.42.164.22.200.19.73.91.70.80.114.155.0.121.249.106.51],
       [151.162.123.68.107.248.237.187.47.168.193.175.84.164.168.142.234.207.201.222.133.60.100.222.113.37.253.5],
       [  9.13.96.226.240.99.3.132.88.138.174.255.209.38.99.20.128.228.148.226.86.195.58.184.142.30.115.216],
       [ 15.163.1.211.13.211.209.24.193.218.245.132.235.247.2.227.25.7.212.139.51.99.249.62.26.247.218.182],
       [198.122.5.117.50.137.148.48.82.235.119.252.43.144.138.216.248.148.124.86.144.35.27.14.144.1.222.106],
       [255.144.105.122.215.154.182.209.203.49.55.43.153.115.188.73.207.4.82.46.91.9.215.15.238.120.23.158],
       [ 81.236.124.56.221.19.169.230.82.248.109.199.55.34.2.158.173.34.25.95.208.201.21.235.70.48.238.2],
       [217.133.10.57.19.148.242.151.157.84.196.111.251.155.158.68.27.131.33.254.70.34.50.171.235.137.15.79],
       [102.230.120.23.211.160.37.51.221.252.41.207.112.106.135.193.133.165.43.253.21.149.145.218.80.126.60.224],
       [230.123.24.90.86.37.85.155.57.216.15.56.146.89.17.197.161.52.176.114.198.216.129.143.174.5.49.184],
       [ 28.205.153.105.237.52.151.33.74.22.215.83.51.106.81.18.6.143.1.186.121.100.101.240.106.205.25.54],
       [ 26.76.136.86.45.159.157.108.189.112.123.209.189.247.221.214.124.117.152.234.204.166.42.137.154.25.194.144],
       [123.123.182.111.41.196.119.91.34.63.123.98.143.231.234.248.29.107.42.63.26.196.232.166.23.244.216.45],
       [108.189.247.78.166.188.239.194.63.239.147.211.91.159.29.55.50.254.37.51.18.128.156.3.125.90.145.75],
       [177.217.104.209.169.231.92.16.10.248.22.34.13.127.115.152.113.241.117.224.68.74.42.126.73.161.203.6],
       [ 50.115.172.9.112.161.156.30.114.229.4.170.219.198.125.25.112.194.87.100.67.212.60.85.165.156.140.44]])
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plt.imshow(image)
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# cmap = "Greys" gray level
plt.imshow(image,cmap="Greys")
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The source code to learn

help(np.random.randint)

elp on built-in function randint:

randint(...) method of numpy.random.mtrand.RandomState instance
    randint(low, high=None, size=None, dtype=int)
    
    Return random integers from `low` (inclusive) to `high` (exclusive).
    
    Return random integers from the "discrete uniform" distribution of
    the specified dtype in the "half-open" interval [`low`, `high`). If
    `high` is None (the default), then results are from [0, `low`).
    
    .. note::
        New code should use the ``integers`` method of a ``default_rng()``
        instance instead; please see the :ref:`random-quick-start`.

......
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Learning to recommend

  • Python documentation – English
  • Python documentation – Chinese
  • Python code PEP
  • Google version of the Python specification
  • Python source code
  • Python PEP
  • Optimal kirin
  • The nuggets platform
  • Gitee platform

 

Python is open source, cross-platform, interpretive, interactive, and worth learning. Python’s design philosophy: elegant, unambiguous, simple. Advocate one way, preferably only one way to do one thing. Code should be written in accordance with specifications to facilitate communication and understanding. Every language has its own unique ideas. Beginners need to change their thinking, practice and accumulate.