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### Python Matplotlib

• date 8th March, 2021 |
• by Prwatech |

### Python Matplotlib for Beginners

Prerequisites

Hardware : Local Machine

Software : Jupyter Notebook

Programming Language : Python

Definition:

Matplotlib is a cross-platform, data visualization and graphical plotting for Python.

Jupyter Notebook Introduction:

Jupyter is a free, open-source, interactive web tool which known as a computational notebook, which anybody can use to combine software code to get the computational output, explanatory text in a single document.

PLOT A LINE IN Matplotlib:

You can run the following code in Jupyter Notebook:

Click this link to open Jupyter Notebook – https://jupyter.org/

plt.plot() –

A function which is used to plot the points between x and y.

plt.show()

Function which shows the plot.

What is Matplotlib?

matplotlib.pyplot is a collection of command style functions which makes matplotlib work like MATLAB

Each `pyplot` function can make any changes to a figure. For example It can create a figure, It can also create a plotting area in the figure, A function which plots some lines in a plotting area

What is Pyplot?

Pyplot package can be considered as `plt`.

SIMPLE PLOT:

Let’s display a simple line plot by using the math module which uses mathematical functions.

Here is the program for the reference Simple Plot:

What is Numpy?

NumPy is a module for the Python programming language for large multi-dimensional arrays and matrices

import numpy as np – In simple terms making short “numpy” to “np” to make your code easier to read.

import math – . The math module uses mathematical functions

np.arrange()

NumPy `arange()` Creation of an array using routines based on numerical ranges. It is also for Setting the coordinates

np.sin() –

It is a mathematical function which helps user to calculate trignometric sine.

plt.plot() –

A function which is used to plot the points between x and y.

MULTI PLOT:

This allows to draw multiple graphs in a single plot.

A subplot () function is known as wrapper function which allows user to plot more than one graph in a single figure

Here is the program for the reference Multi Plot:

plt.plot([1, 2, 3)]

Plot a line, Implicitly creating a subplot

What is a Subplot?

Subplots can connect to main plots.

plt.subplot(211)

Creation of a subplot that represents the top plot of a grid with 2 rows and 1 column.

plt.subplot(212, facecolor=’y’)

As we can see it creates 2nd subplot with yellow background

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BAR PLOT:

A bar graph is the visualization which shows the comparison among discrete categories. X axis of the chart shows the categories which are compared, and Y axis represents a measured value.

Here is the program for reference for Bar Plot:

fig = plt.figure()

figure() A function which is used to create a figure object.

` `

It is a figure module of matplotlib which is used to add axes to the figure.

ax.bar()

A module of matplotlib is used to make a bar plot.

plt.show()

Function to show the plot.

HISTOGRAM:

A histogram represents the numerical data. It is also known as the other form of Bar Graph.

Here is the program for the reference Histogram:

np.array()

A function which includes Array elements

ax.hist()

It is an essential function that is to plot a histogram graph.

ax.set()

A function which is know to be a property, In other words it is a batch setter, Be it Title set or a Label Set

plt.show()

A function to show the plot.

### PIE CHART:

A Pie Chart displays one series of data. Pie charts shows the size of subjects in one data series in different divisions, The data points are shown in percentage in a Pie chart.

Here is the program for the reference Pie Chart:

import numpy as np

In simple terms making short “numpy” to “np” to make your code easier to read.

fig = plt.figure()

figure() A function which is to create a figure object.

ax.pie

A function of Matplotlib library which is to plot a pie chart Graph.

plt.show()

A function to show the plot.

Matplotlib – Scatter Plot

Scatter plots are knows to be of plotting data points on horizontal and vertical axis in the attempt to show how much one variable is affected by another.

A scatter plot is a diagram which is displayed in a graphical format where each value in the data set is represented by a single dot.

Here is a program for the reference Scatter Plot:

fig = plt.figure()

figure() A function which is to create a figure object.

ax.scatter

It is a module of Matplotlib library which is to plot a scatter plot graph.

ax.set_title()

To set the Title on the Top of the Graph

#### CONTOUR PLOT

Contour plots displays a 3 dimensional surface on 2 – dimensional plane.

Here is the program for the reference Contour Plot:

np.linespace

The nplinspace is a tool in Python for creating numeric sequences. It is kind of similar to np.arrange() function.

np.meshgrid

The `numpy.meshgrid` function is used to create a rectangular grid out of two given 1 – dimensional arrays.

np.sqrt

A Function which is to determine the positive square-root of an array, in a specific way, element-wise.

ax.contour

It is a function of matplotlib is to Plot contours. contourdraw contour lines.

fig.colorbar(cp)

It is a function of matplotlib is  to add a color bar to a plot.

ax.set_title()

To set the Title on the Top of the Graph

plt.show()

A function to show the plot.

QUIVER PLOT

A quiver plot displays the velocity vectors as arrows with components.

` `

Here is the program for the reference Quiver Plot:

VIOLIN PLOT

Violin plots are identical to box plots, exception is that they also show the probability density of the data at different pace of values.

A violin plot is much more informative than a plain box plot.

Here is the program for the reference Violin Plot:

3 D CONTOUR PLOT

ax.contour3D()

It is a function creates three-dimensional contour plot.

Here is the program for the reference 3D Contour Plot:

Output:

3D WIREFRAME PLOT

Wireframe plot takes a grid of values and projects it onto the specified three-dimensional surface

Here is the program for the reference 3D Wireframe plot:

Output:

GRIDS

The grid() function of axes object sets visibility of grid inside the figure to on or off.

Here is the program for the reference Grids:

Output:

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