Python中的 matplotlib.axes.Axes.pie()

Matplotlib是Python中的一个库，它是 NumPy 库的数值数学扩展。 Axes 类包含大部分图形元素：Axis、Tick、Line2D、Text、Polygon 等，并设置坐标系。 Axes 的实例通过回调属性支持回调。

matplotlib.axes.Axes.pie()函数

matplotlib 库的 axes 模块中的Axes.pie()函数用于绘制饼图。

Syntax: Axes.pie(self, x, explode=None, labels=None, colors=None, autopct=None, pctdistance=0.6, shadow=False, labeldistance=1.1, startangle=None, radius=None, counterclock=True, wedgeprops=None, textprops=None, center=(0, 0), frame=False, rotatelabels=False, *, data=None)

Parameters: This method accept the following parameters that are described below:

• x: This parameter is the wedge sizes.
• explode: This parameter is the is a len(x) array which specifies the fraction of the radius with which to offset each wedge.
• autopct: This parameter is a string or function used to label the wedges with their numeric value.
• colors: This parameter is the sequence of matplotlib color args through which the pie chart will cycle.
• label: This parameter is the sequence of strings providing the labels for each wedge.
• pctdistance: This parameter is the ratio between the center of each pie slice and the start of the text generated by autopct.
• shadow: This parameter is the used to draw a shadow beneath the pie.
• labeldistance: This parameter is the radial distance at which the pie labels are drawn.
• startangle: This parameter is used to rotates the start of the pie chart by angle degrees counterclockwise from the x-axis.
• radius: This parameter is the radius of the pie.
• counterclock: This parameter specifies fractions direction, clockwise or counterclockwise.
• wedgeprops: This parameter is dict of arguments passed to the wedge objects making the pie.
• textprops: This parameter is dict of arguments to pass to the text objects.
• center: This parameter is the Center position of the chart.
• frame: This parameter is used to plot axes frame with the chart if true.
• rotatelabels: This parameter is used to rotate each label to the angle of the corresponding slice if true.

Returns: This returns the following:

• patches: This returns the sequence of matplotlib.patches.Wedge instances.
• texts: This returns the list of the label matplotlib.text.Text instances.
• autotexts: This returns the list of Text instances for the numeric labels.

下面的示例说明了 matplotlib.axes 中的 matplotlib.axes.Axes.pie()函数：

示例 #1：

# Implementation of matplotlib function
import matplotlib.pyplot as plt
  
labels = 'Geek1', 'Geek2', 'Geek3', 'Geek4'
sizes = [10, 20, 30, 40]
explode = (0.1, 0, 0, 0)
  
fig1, ax1 = plt.subplots()
ax1.pie(sizes, explode = explode,
        labels = labels, autopct ='% 1.1f %%',
        shadow = True, startangle = 90)
ax1.axis('equal')
  
ax1.set_title('matplotlib.axes.Axes.pie Example')
plt.show()

输出：

示例 #2：

# Implementation of matplotlib function
import matplotlib.pyplot as plt
import numpy as np
  
fig, ax = plt.subplots()
  
size = 0.3
vals = np.array([[90, 43], [57, 60],
                 [92, 20]])
  
cmap = plt.get_cmap("tab20c")
outer_colors = cmap(np.arange(3)*4)
mid_colors = cmap(np.array([1, 2, 3, 4, 5, ]))
inner_colors = cmap(np.array([4, 12, 5, 
                              6, 9, 10]))
  
ax.pie(vals.sum(axis = 1), radius = 1, 
       colors = outer_colors,
       wedgeprops = dict(width = size, 
                         edgecolor ='w'))
  
ax.pie(vals.flatten(), radius = 1-size, 
       colors = mid_colors,
       wedgeprops = dict(width = size,
                         edgecolor ='w'))
  
ax.pie(vals.flatten(), radius = 1-2 * size,
       colors = inner_colors,
       wedgeprops = dict(width = size, 
                         edgecolor ='w'))
  
ax.set_title('matplotlib.axes.Axes.pie Example')
plt.show()