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Using Matplotlib To Draw Line Between Points

In this tutorial, let us learn how to use Matplotlib to draw line between two points. Matplotlib is a Python library package that we can use to draw lines, charts and other plots. It takes in datasets as its input and converts them into plots and graphs. Therefore, it can help us in visualizing and interpreting our datasets is a much more better way.

In order for us to be able to use Matplotlib to draw line between two points, first ensure that Matplotlib is installed on your computer. Once it is confirmed, let us now first create a set of data points that we want to plot.

Creating dataset for Matplotlib to draw line between points

One of the simplest way for us to create our dataset is by calling Python’s built-in range function.

Check this tutorial to learn more about Python’s built-in range function.

So, let us now start writing our Python plotting program:

import matplotlib.pyplot as plt

In this line of code, we are simply importing the pyplot submodule of the Matplotlib library as plt. Hence from now onwards we can call it by simply calling the plt variable.

Next, let us generate our desired dataset using Python’s range function.

x = range(5)

As can be seen here, we are asking the range function to provide us with a sequence of integers from 0 to 4. That is because mentioning an upper limit of 5, we have limited the range between 0 to 5. The step size will also default to 1. As a result, our dataset will now look like this:

x = [0, 1, 2, 3, 4]

So now that we have our dataset, its time to plot these values using Matplotlib.

Using Matplotlib to draw line between points

Since we have already imported Matplotlib’s Pyplot submobule, we can right away start using it to plot our line. Pyplot provides us with a very handy helper function called plot to plot our line.

The general syntax of our plot function looks like this:

plot([x], y, [fmt], *, data=None, **kwargs)

As can be seen above, plot takes in an optional x-axis value. However y-axis values are a must for plot function to work. On the other hand, plot function also takes in additional parameters such as an optional [fmt], data etc. You can refer to the official documentation for this function to learn more about how to use it.

However, for our case, we will simply use our dataset as our y-axis parameters. Since x-axis is optional, we can leave it blank. By doing so, Matplotlib will automatically start filling in these values starting with a value of 0 and incrementing it by 1 for each extra intervals. Hence, our code for plotting will simply look like this:

plt.plot([xi for xi in x])

What we are doing here is simply passing each of the values of our dataset x as plot functions y-axis parameters.

However, we are still not done here. The code written up until now would have drawn our line connecting the points of data. However, in order for us to be able to display it to the end user, we need to call another function called the “show” function. So, we still need to add this final line of code into our program:

plt.show()

With this, we should be able to see a plot drawn by Matplotlib that is drawing a line between our data points. It looks something like this:

Final result image of using Matplotlib to draw line between points
Line between points drawn using Matplotlib

Conclusion

Combining all the above piece of code in a single place will give our final code that looks like below:

import matplotlib.pyplot as plt
x = range(5)
plt.plot([xi for xi in x])
plt.show()

So this is it! With just these four lines of code, we are able to make use of Matplotlib to draw line between points. I hope this tutorial was pretty straight forward. If you have any more queries or simply want to say hi to me, please leave a comment below! Until next time, ciao!

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