Pie Charts in Octave

In this online lesson, I will show you how to create a pie chart using Octave.

What is a pie chart? Also known as a pie graph or circle graph, it is a circular graph that displays categories as slices of a whole, with each slice representing a percentage.

Here's a practical example.

First, create an array with some values.

>> x = [ 5 , 10 , 15 ];

The total of the array is 5 + 10 + 15 = 30.

To draw a pie chart of the array x, use the pie() function.

>> pie(x)

This will give you the pie chart of the data.

As you can see, in the pie chart, the value 15 represents half of the chart because it is 50% of the total (30).

The other values, 10 and 5, have smaller slices, representing 33% and 17%, respectively.

If you want to separate one or more slices from the pie, create another array where you indicate the edges of the slices.

For example, apply an edge of 1 to the smallest slice to remove it from the chart while leaving the other slices intact.

>> b = [ 1 , 0 , 0 ];

The array "b" must have the same number of elements as the array "x," in this case, three.

Now, redraw the pie chart using the pie() function and both arrays.

>> pie(x,b)

The first slice is now separated from the pie chart.

If you want to display labels instead of percentages, create an array of cells.

>> label={"pens","pencils","erasers"};

Then, redraw the pie chart and add the "label" array as a third parameter.

>> pie(x,b,label)

Each slice is now associated with a label.

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