3.8 Pie Chart

A Pie Chart can only display one series of data. Pie charts show the size of items (called wedge) in one data series, proportional to the sum of the items.

Parameters	Description
x	array-like. The wedge sizes.
labels	A list. A sequence of strings providing the labels for each wedge.
colors	A sequence of matplotlib color args through which the pie chart will cycle.
autopac	A string used to label the wedges with their numeric value. The label will be placed inside the wedge.

1. Basic Pie Chart

plt.figure(1,figsize = (6,6))

labels = ['Apple', 'Banana', 'Orange', 'Kiwi']
sizes = [38.4, 40.6, 20.7, 10.3]
colors = ['yellowgreen', 'gold', 'lightskyblue', 'lightcoral']
patches, texts = plt.pie(sizes, colors=colors, shadow=True, startangle=90)
plt.legend(patches, labels, loc="best")
plt.axis('equal')
plt.tight_layout()
plt.show()

Basic Pie Chart

Now we have a basic pie chart. Of course, it can be and should be presented better.

For example, the legend position is weird and overlapped with the pie. Also, we can not see any numbers from it and we don't know which part we should focus on. Therefore, Let's do some changes.

2. Fancy Pie Chart

plt.figure(1,figsize = (6,6))
labels = ['Apple', 'Banana', 'Orange', 'Kiwi']
sizes = [38.4, 40.6, 20.7, 10.3]
colors = ['yellowgreen', 'gold', 'lightskyblue', 'lightcoral']
explode = (0, 0.1, 0, 0)  #explode 1st slice

plt.pie(sizes, explode=explode, labels=labels, colors=colors,
autopct='%1.1f%%', shadow=True, startangle=-45)  # add shadow, show percentage
plt.axis('equal')
plt.title('Fancy Pie Chart')

Fancy Pie Chart

3. Donut Chart

plt.figure(1,figsize = (6,6))
labels = ['Apple', 'Banana', 'Orange', 'Kiwi']
sizes = [38.4, 40.6, 20.7, 10.3]
colors = ['yellowgreen', 'gold', 'lightskyblue', 'lightcoral']

plt.pie(sizes, labels=labels, colors=colors,
autopct='%1.1f%%', startangle=-45, shadow=True) 

#draw circle
centre_circle = plt.Circle((0,0),0.75,fc='white') #0.75 is the circle size
fig = plt.gcf()
fig.gca().add_artist(centre_circle)

plt.axis('equal')
plt.title('Donut Chart')

Donut Chart

As we discussed in Features of Pie Chart, Pie charts are poor at communicating data, especially for complicated data. Although it looks awesome, it delivers less information than tables or column charts.

• Simple is better than complex.

• Readability counts. Do not make it hard to read.