Python: Matplotlib

last updated: 2021-07-06]
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(link to:) matplotlib.org - troubleshooting
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• Install it with:
  $ pip install matplotlib
  (See here to verify that pip is installed)

• Verify matplotlib is installed:
  Run this python program:
  #!/usr/bin/python
  import matplotlib
  print ('matplotlib version: ' + matplotlib.__version__)
  print ('prog end')
  # end program

• If generating or analyzing your data requires calculations,
  it's recommended to use numpy,
  which is a library with support for large, multi-dimensional arrays and matrices, along with a large collection of high-level mathematical functions to operate on these arrays.
  Wikipedia

  pip install numpy
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• Demo program:
  (edited from: https://www.geeksforgeeks.org/graph-plotting-in-python-set-1/)
  code: demoPlot-03.py.txt
  Loaded onto Dell-4600
  Executed from terminal with:
  $ sudo python3 ~/Documents/myFiles/workingFiles-4600/Tech-some/Linux/python/testProgs/demoPlot-03.py

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• Plot options:
  • The line in your python program that specifies and draws the plot is:
    plt.plot (x, y)

    This will create the plot using default parameter values.

  • Conversely, if you want to change things, you can specify values for plot parameters with:
    plt.plot (x, y, color='green', linestyle='solid', linewidth = 3,
    marker='o', markerfacecolor='blue', markersize=10)

  • Plot two lines:
    • Define two data sets:
      x1 = [1,2,3]
      y1 = [2,3,4]
      x2 = [1,2,3]
      y2 = [4,1,3]
    • Plot first line:
      plt.plot(x1, y1, label = "line 1")
    • Plot second line:
      plt.plot(x2, y2, label = "line 2")
    • Show a legend on the graph:
      plt.legend()

  • Lots of other options:
    • bar charts, pie charts, plus others
    • multiple plots on same figure
    • 3d plots
    • plus more...

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• Animation:
  • https://www.geeksforgeeks.org/graph-plotting-python-set-3/
  • The Animation tools in matplotlib are centered around the matplotlib.animation base class.
    This is the framework. The main interfaces are:
    TimedAnimation, and
    FuncAnimation.
    FuncAnimation is the most convenient one to use.

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