The document provides an introduction to the matplotlib library, detailing its capabilities for creating visualizations in Python. It discusses installation via pip, basic functions such as plot and show, and how to create figures and subplots. Additionally, it addresses turning on interactive mode for real-time programming feedback.

1. The matplotlib Library
Haim Michael
October 14th
, 2020
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What is Matplotlib?
 Matplotlib is a library that allows us to create static,
animated, and interactive visualizations in Python.

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Installing Matplotlib
 The simplest way to install matplotlib would be to install it
using the pip utility.
pip install matplotlib

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The plot Function
 There are various ways to use the matplotlib library for
drawing diagrams. The simplest would be using the plot
function, that was defined inside the matplotlib.pyplot
module, passing over the x and the y coordinates.

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The show Function
 Once completed, calling show will draw the diagram on the
screen.
import matplotlib.pyplot as plt
import numpy as np
plt.plot([1,2,3,4], [4,3,2,1], label='linear')
plt.legend()
plt.show()

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The show Function

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The Figure Class
 When instantiating matplotlib.figure.Figure class
we get an object that represents a window (or a page) on
which everything will be plotted.

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The add_subplot Method
 We can invoke add_sublot on a Figure object in order to
add axes for plotting a diagram.

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The add_subplot Method
import matplotlib.pyplot as plt
import numpy as np
fig = plt.figure()
ax = fig.add_subplot()
ax.scatter([1,2,3,4,5],[4,3,7,8,20])
plt.show()

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The subplots Function
 We can invoke the sublots function that was defined in the
matplotlib.pyplot module and get a tuple that holds a
reference for a Figure object and a reference for an Axes
object.

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The subplots Function
import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(0, 2, 20)
fig, ax = plt.subplots()
ax.plot(x, x, label='x=x')
ax.plot(x, x**2, label='x=x**2')
ax.plot(x, x**3, label='x=x**3')
ax.set_xlabel('x label')
ax.set_ylabel('y label')
ax.set_title("Simple Plot")
ax.legend()
plt.show()

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The Interactive Mode
 We can turn on the interactive mode by calling the ion()
function.
 Doing so when using a Python console we will be able to
continue the execution of more statements in the Python
Console and while doing so, get to see the immediate
outcome.

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The Interactive Mode

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The plot() Function
 The plot() method that was defined inside the
matplotlib.pyplot module can be invoked in various
ways.
 The plot() method that was defined inside the
matplotlib.pyplot module can be invoked in various
ways.

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The plot() Function
import matplotlib.pyplot as plt
import numpy as np
t = np.arange(0, 4, 0.1)
plt.plot(t, t, 'g--', t, t**2, 'bs', t, t**3, 'r^')
plt.show()

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Q & A
 Thanks!
haim.michael@lifemichael.com
054-6655837
http://blog.lifemichael.com