Getting Started with Matplotlib
Hey there! In this article, I’ll walk you through the next steps after installing and importing Matplotlib
Pyplot
Most of the Matplotlib utilities lies under the pyplot submodule, and are usually imported under the plt alias:
import matplotlib.pyplot as plt
Now the Pyplot package can be referred to as plt.
Example
Draw a line in a diagram from position (0,0) to position (6,250):
import matplotlib.pyplot as plt
import numpy as npxpoints = np.array([0, 6])
ypoints = np.array([0, 250])plt.plot(xpoints, ypoints)
plt.show()
Result:
Plotting x and y points
The plot() function is used to draw points (markers) in a diagram.
By default, the plot() function draws a line from point to point.
The function takes parameters for specifying points in the diagram.
Parameter 1 is an array containing the points on the x-axis.
Parameter 2 is an array containing the points on the y-axis.
Plotting Without Line
To plot only the markers, you can use shortcut string notation parameter ‘o’, which means ‘rings’.
Example
Draw two points in the diagram, one at position (1, 3) and one in position (8, 10):
import matplotlib.pyplot as plt
import numpy as npxpoints = np.array([1, 8])
ypoints = np.array([3, 10])plt.plot(xpoints, ypoints, ‘o’)
plt.show()
Result:
Multiple Points
You can plot as many points as you like, just make sure you have the same number of points on both axis.
Example
Draw a line in a diagram from position (1, 3) to (2, 8) then to (6, 1) and finally to position (8, 10):
import matplotlib.pyplot as plt
import numpy as npxpoints = np.array([1, 2, 6, 8])
ypoints = np.array([3, 8, 1, 10])plt.plot(xpoints, ypoints)
plt.show()
Result:
Default X-Points
If we do not specify the points in the x-axis, they will get the default values 0, 1, 2, 3, (etc. depending on the length of the y-points.
So, if we take the same example as above, and leave out the x-points, the diagram will look like this:
Example
Plotting without x-points:
import matplotlib.pyplot as plt
import numpy as npypoints = np.array([3, 8, 1, 10, 5, 7])plt.plot(ypoints)
plt.show()
Result:
