Matplotlib is a widely used visualization library in Python that allows easy creation of various types of line charts, bar charts, histograms, etc. Since Matplotlib is a visualization library, each example can be quite extensive. Here, we will try to understand this library well with simple and minimal code.

## Installing Matplotlib

Similar to installing other packages, we will install Matplotlib using the pip command. Since we have already learned how to use the pip command, we won’t go into details here. To install Matplotlib, run the following command:

```
pip install matplotlib
```

If everything goes well, you should see something like the image below:

I hope everyone has successfully installed Matplotlib.

## Plotting

In Matplotlib, graphs can be easily drawn using the `plot()`

method. Here, we will show how to create a graph with only y-axis values.

```
import matplotlib.pyplot as plt
import numpy as np
y_value = np.array([3,6,4,1,2])
plt.plot(y_value, marker='*', linestyle='dashed')
plt.title("This is a title")
plt.xlabel("X Value")
plt.ylabel("Y Value")
plt.show()
```

Output:

Here we can see a graph. If we look closely, we will see that points are created at positions (0,3), (1,6), (2,4), (3,1), (4,2). Even though the `y_value`

variable only has the y-axis values, Matplotlib automatically takes the x-axis values one by one.

Notice in the first line, instead of importing `matplotlib`

, we imported `matplotlib.pyplot`

. Pyplot is a sub-module where most of the graph functions are defined.

Points are plotted using `plt.plot()`

. Here, we see an argument named `marker`

, which indicates the design of the points. Instead of `*`

, you can use any Python-supported character. Another argument here is `linestyle`

, which specifies the style of the line. Its values can be `solid`

, `dotted`

, `dashed`

, `dashdot`

, etc. If the `linestyle`

argument is not given, it defaults to `solid`

.

The `plt.title()`

function sets the title of the graph. The text “This is a title” seen above the graph is the title.

`plt.xlabel()`

and `plt.ylabel()`

are used to set the labels for the x-axis and y-axis, respectively. Compare the graph with the result provided.

The `plt.show()`

line is used to display the result.

**Note:** In subsequent examples, we will not use labels or titles.

## Line Graph

The graph we saw above is also a line graph. Now let’s see how to create a graph with multiple points.

```
import matplotlib.pyplot as plt
import numpy as np
x_value = np.array([1,2,5,8])
y_value = np.array([3,6,9,5])
plt.plot(x_value,y_value)
plt.show()
```

Output:

Here, we can see a line graph with specific points.

## Scatter Plot

In a line plot, one point is connected to another, but in a scatter plot, there are no connections. It looks like random points. The `scatter()`

method is used for scatter plots.

```
import matplotlib.pyplot as plt
import numpy as np
x_value = np.random.rand(20) #Genrate 20 random number
y_value = np.random.rand(20) #Genrate 20 random number
plt.scatter(x_value,y_value)
plt.show()
```

Output:

We have drawn a graph using `scatter()`

. For convenience, we used some random numbers in lines 4 and 5. You can try using some real numbers of your choice.

## Bar Chart

Bar charts are used to represent data in bar form. The `bar()`

method is used to create a bar chart.

```
import matplotlib.pyplot as plt
import numpy as np
x_value = np.array(['CSE10','CSE20','CSE30'])
y_value = np.array([4,3.55,2.88])
plt.bar(x_value,y_value)
plt.show()
```

Output:

A plot has been created using the `bar()`

method. Bars are vertical by default, but you can create horizontal bars using the `barh()`

method.

## Pie Chart

We are all somewhat familiar with pie charts. Pie charts are used to represent data as percentages. The `pie()`

method is used to create a pie chart in Matplotlib.

```
import matplotlib.pyplot as plt
import numpy as np
value = [20,20,30,10,20]
label = ['Label1','Label2','Label3','Label4','Label5']
plt.pie(value,labels=label)
plt.show()
```

Output:

A pie chart has been created using the `pie()`

method. Here, we have created some meaningless labels; in real work, we will try to create meaningful labels.