How to create a pie chart using Matplotlib in Python
Overview
A pie chart is a pictorial graph in the shape of a circle, with different wedges or segments representing different data values.
We draw pie charts in matplotlib using the method pie(), which is found in the pyplot module.
Syntax
pyplot.pie()
Parameter value
The pie() method takes the data array which represents the wedge sizes of the pie chart.
Code example
Now let’s explore a basic example of pie chart.
from matplotlib.pyplot import pie, showfrom numpy import arraydata_set = array([25, 20, 50, 15])pie(data_set)show()
Code explanation
-
Line 1: We import
pie()andshow()from thematplotlib.pyplotmodule. -
Line 2: We import
array()fromNumPylibrary. -
Line 4: We use the
array()method to create a data array. -
Line 6: We use the
pie()method to plot a pie chart. -
Line 7: We use the
show()method to show our plot.
After exploring the basic example, let's enhance our understanding with an example of a pie chart with some customization.
from matplotlib.pyplot import pie, showfrom numpy import arraydata_set = array([25, 20, 50, 15])labels = ['A', 'B', 'C', 'D']colors = ['gold', 'yellowgreen', 'lightcoral', 'lightskyblue']explode = (0, 0.1, 0, 0) # "explode" the second slice (B)pie(data_set, explode=explode, labels=labels, colors=colors, autopct='%1.1f%%', shadow=True)show()
Line 1: This line imports the
pie()andshow()functions from thematplotlib.pyplotmodule.pie()is used to create pie charts, whileshow()is used to display the plot.Line 2: Here, we import the
array()function from the NumPy library. This function is used to create an array, a fundamental data structure in numerical computing.Line 4: We define a dataset using the
array()function. In this case, we create an array with values[25, 20, 50, 15], which represent the sizes of different slices in the pie chart.Line 5: We defined am
labelsvariable, which a list of strings (['A', 'B', 'C', 'D']) representing the labels assigned to each slice of the pie chart. These labels will be displayed next to their respective slices.Line 6: We defined a variable called colors, which is a list of color names or RGB tuples (
['gold', 'yellowgreen', 'lightcoral', 'lightskyblue']) specifying the colors of the pie chart slices. Each color corresponds to a specific slice, providing visual differentiation.Line 9: This line calls the
pie()function to create a pie chart. We pass thedata_setarray as an argument to the function, which specifies the sizes of the slices in the pie chart.Line 10: Finally, we call the
show()function to display the plot on the screen. This function is necessary to actually render the plot and show it to the user.
