Author: Mostafa

Python Matplotlib Scatter

Creating Scatter Plots

With Pyplot, you can use the scatter() function to draw a scatter plot.

The scatter() function plots one dot for each observation. It needs two arrays of the same length, one for the values of the x-axis, and one for values on the y-axis:

Example

A simple scatter plot:

import matplotlib.pyplot as plt
import numpy as np

x = np.array([5,7,8,7,2,17,2,9,4,11,12,9,6])
y = np.array([99,86,87,88,111,86,103,87,94,78,77,85,86])

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

 

The observation in the example above is the result of 13 cars passing by.

The X-axis shows how old the car is.

The Y-axis shows the speed of the car when it passes.

Are there any relationships between the observations?

It seems that the newer the car, the faster it drives, but that could be a coincidence, after all we only registered 13 cars. Continue reading Python Matplotlib Scatter

Python Matplotlib Subplot

Display Multiple Plots

With the subplot() function you can draw multiple plots in one figure:

Example

Draw 2 plots:

import matplotlib.pyplot as plt
import numpy as np

#plot 1:
x = np.array([0, 1, 2, 3])
y = np.array([3, 8, 1, 10])

plt.subplot(1, 2, 1)
plt.plot(x,y)

#plot 2:
x = np.array([0, 1, 2, 3])
y = np.array([10, 20, 30, 40])

plt.subplot(1, 2, 2)
plt.plot(x,y)

plt.show()

 

Continue reading Python Matplotlib Subplot

Python Matplotlib Adding Grid Lines

Add Grid Lines to a Plot

With Pyplot, you can use the grid() function to add grid lines to the plot.

Example

Add grid lines to the plot:

import numpy as np
import matplotlib.pyplot as plt

x = np.array([80, 85, 90, 95, 100, 105, 110, 115, 120, 125])
y = np.array([240, 250, 260, 270, 280, 290, 300, 310, 320, 330])

plt.title("Sports Watch Data")
plt.xlabel("Average Pulse")
plt.ylabel("Calorie Burnage")

plt.plot(x, y)

plt.grid()

plt.show()

 

Continue reading Python Matplotlib Adding Grid Lines

Python Matplotlib Labels and Title

Create Labels for a Plot

With Pyplot, you can use the xlabel() and
ylabel() functions to set a label for the x- and y-axis.

Example

Add labels to the x- and y-axis:

import numpy as np
import matplotlib.pyplot as plt

x = np.array([80, 85, 90, 95, 100, 105, 110, 115, 120, 125])
y = np.array([240, 250, 260, 270, 280, 290, 300, 310, 320, 330])

plt.plot(x, y)

plt.xlabel("Average Pulse")
plt.ylabel("Calorie Burnage")

plt.show()

 

Continue reading Python Matplotlib Labels and Title

Python Matplotlib Line

Linestyle

You can use the keyword argument linestyle, or shorter ls, to change the style of the plotted line:

Example

Use a dotted line:

import matplotlib.pyplot as plt
import numpy as np

ypoints = np.array([3, 8, 1, 10])

plt.plot(ypoints, linestyle = 'dotted')
plt.show()

Example

Use a dashed line: Continue reading Python Matplotlib Line

Python Matplotlib Markers

Markers

You can use the keyword argument marker to emphasize each point with a specified marker:

Example

Mark each point with a circle:

import matplotlib.pyplot as plt
import numpy as np

ypoints = np.array([3, 8, 1, 10])

plt.plot(ypoints, marker = 'o')
plt.show()

 

Continue reading Python Matplotlib Markers

Python Matplotlib Plotting

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.

If we need to plot a line from (1, 3) to (8, 10), we have to pass two arrays [1, 8] and [3, 10] to the plot function. Continue reading Python Matplotlib Plotting

Python Matplotlib Pyplot

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. Continue reading Python Matplotlib Pyplot

Python Matplotlib Getting Started

Installation of Matplotlib

If you have Python and PIP already installed on a system, then installation of Matplotlib is very easy.

Install it using this command:

C:\Users\Your Name>pip install matplotlib

If this command fails, then use a python distribution that already has Matplotlib installed,  like Anaconda, Spyder etc.

Continue reading Python Matplotlib Getting Started

Python Matplotlib Tutorial

What is Matplotlib?

Matplotlib is a low level graph plotting library in python that serves as a visualization utility.

Matplotlib was created by John D. Hunter.

Matplotlib is open source and we can use it freely.

Matplotlib is mostly written in python, a few segments are written in C, Objective-C and Javascript for Platform compatibility.

Continue reading Python Matplotlib Tutorial