about "matplotlib" 
    https://aiacademy.jp/media/?p=154 
    https://matplotlib.org/

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# how to use: module "pyplot" in the package "matplotlib"

import matplotlib.pyplot

x = [0,1,2,3,4,5,6,7,8,9,10]
y = [0, 1, 0, 3, 2, 8, 10, 4, 5, 3, 4]

matplotlib.pyplot.plot(x,y) 
matplotlib.pyplot.show()

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# how to use: "as"

import matplotlib.pyplot as plt

x = [0,1,2,3,4,5,6,7,8,9,10]
y = [0, 1, 0, 3, 2, 8, 10, 4, 5, 3, 4]

plt.plot(x,y) 
plt.show()

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# how to use:   change colors

import matplotlib.pyplot as plt

x = [0,1,2,3,4,5,6,7,8,9,10]
y = [0, 1, 0, 3, 2, 8, 10, 4, 5, 3, 4]

plt.plot(x,y,"r--") 
plt.show()

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# multiple graphs, y1, y2

import matplotlib.pyplot as plt

x = [0,1,2,3,4,5,6,7,8,9,10]
y1 = [0, 1, 0, 3, 2, 8, 10, 4, 5, 3, 4]
y2 = [7, 8, 4, 9, 0, 3, 1, 9, 6, 5, 10]

plt.plot(x,y1,"r--") 
plt.plot(x,y2,"g--")
plt.show()

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# bar graph

import matplotlib.pyplot as plt

x = [0,1,2,3,4,5,6,7,8,9,10]
y = [0, 1, 0, 3, 2, 8, 10, 4, 5, 3, 4]

plt.bar(x,y) 
plt.show()