關於matplotlib,你要的餅圖在這裡

Table of Contents

1  官方Demo

2  將實際數據應用於官方Demo

3  一些改善措施

3.1  重新設置字體大小

3.2  設置顯示顏色，Method 1：

3.3  設置顯示顏色， Method 2：

3.4  設置圖例（legend）

3.5  重新設置圖例（legend）

3.6  將某些類別突出顯示

# 前言

matplotlib， 官方提供的餅圖Demo，功能比較比較簡單，在實際應用過程中，往往會有許多個性化的繪製需求，在這裡跟大家一起了解下餅圖（pie chart）的一些特色的功能的實現。

from matplotlib import font_manager as fm

import matplotlib as mpl

import pandas as pd

import numpy as np

import matplotlib.pyplot as plt

% matplotlib inline

plt.style.use('ggplot')

1. 官方Demo

import matplotlib.pyplot as plt

# Pie chart, where the slices will be ordered and plotted counter-clockwise:

labels = 'Frogs', 'Hogs', 'Dogs', 'Logs'

sizes = [15, 30, 45, 10]

explode = (0, 0.1, 0, 0)  # only "explode" the 2nd slice (i.e. 'Hogs')

fig1, ax1 = plt.subplots()

ax1.pie(sizes, explode=explode, labels=labels, autopct='%1.1f%%',

       shadow=True, startangle=90)

ax1.axis('equal')  # Equal aspect ratio ensures that pie is drawn as a circle.

plt.savefig('Demo_official.jpg')

plt.show()

2. 將實際數據應用於官方Demo

# 原始數據

shapes = ['Cross', 'Cone', 'Egg', 'Teardrop', 'Chevron', 'Diamond', 'Cylinder',

      'Rectangle', 'Flash', 'Cigar', 'Changing', 'Formation', 'Oval', 'Disk',

      'Sphere', 'Fireball', 'Triangle', 'Circle', 'Light']

values = [  287,   383,   842,   866,  1187,  1405,  1495,  1620,  1717,

       2313,  2378,  3070,  4332,  5841,  6482,  7785,  9358,  9818, 20254]

s = pd.Series(values, index=shapes)

s

from matplotlib import font_manager as fm

import matplotlib as mpl

# Pie chart, where the slices will be ordered and plotted counter-clockwise:

labels = s.index

sizes = s.values

explode = (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)  # only "explode" the 1st slice

fig1, ax1 = plt.subplots()

patches, texts, autotexts = ax1.pie(sizes, explode=explode, labels=labels, autopct='%1.0f%%',

       shadow=False, startangle=170)

ax1.axis('equal')  # Equal aspect ratio ensures that pie is drawn as a circle.

plt.savefig('Demo_project.jpg')

plt.show()

上圖的一些問題：

顏色比較生硬

部分文字擁擠在一起，繪圖顯示不齊整

3. 一些改善措施

重新設置字體大小

設置自選顏色

設置圖例

將某些類別突出顯示

3.1 重新設置字體大小

from matplotlib import font_manager as fm

import matplotlib as mpl

labels = s.index

sizes = s.values

explode = (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)  # only "explode" the 1st slice

fig1, ax1 = plt.subplots()

patches, texts, autotexts = ax1.pie(sizes, explode=explode, labels=labels, autopct='%1.0f%%',

       shadow=False, startangle=170)

ax1.axis('equal')  # Equal aspect ratio ensures that pie is drawn as a circle.

# 重新設置字體大小

proptease = fm.FontProperties()

proptease.set_size('xx-small')

# font size include: 『xx-small』,x-small』,'small』,'medium』,『large』,『x-large』,『xx-large』 or number, e.g. '12'

plt.setp(autotexts, fontproperties=proptease)

plt.setp(texts, fontproperties=proptease)

plt.savefig('Demo_project_set_font.jpg')

plt.show()

3.2 設置顯示顏色，Method 1：

from matplotlib import font_manager as fm

import matplotlib as mpl

# Pie chart, where the slices will be ordered and plotted counter-clockwise:

labels = s.index

sizes = s.values

explode = (0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)  # only "explode" the 1st slice

fig1, ax1 = plt.subplots(figsize=(6,6)) # 設置繪圖區域大小

a = np.random.rand(1,19)

color_vals = list(a[0])

my_norm = mpl.colors.Normalize(-1, 1) # 將顏色數據的範圍設置為 [0, 1]

my_cmap = mpl.cm.get_cmap('rainbow', len(color_vals)) # 可選擇合適的colormap，如：'rainbow'

patches, texts, autotexts = ax1.pie(sizes, explode=explode, labels=labels, autopct='%1.0f%%',

       shadow=False, startangle=170, colors=my_cmap(my_norm(color_vals)))

ax1.axis('equal')  

# 重新設置字體大小

proptease = fm.FontProperties()

proptease.set_size('xx-small')

# font size include: 『xx-small』,x-small』,'small』,'medium』,『large』,『x-large』,『xx-large』 or number, e.g. '12'

plt.setp(autotexts, fontproperties=proptease)

plt.setp(texts, fontproperties=proptease)

plt.savefig('Demo_project_set_color_1.jpg')

plt.show()

上面這種方法設置顏色時，但類別比較多時，部分顏色的填充會重複。

有時候，我們可能想設置成連續的顏色，可以有另外一種方法來實現。

3.3 設置顯示顏色， Method 2：

from matplotlib import font_manager as fm

from  matplotlib import cm

labels = s.index

sizes = s.values

# explode = (0.2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)  # only "explode" the 1st slice

fig, ax = plt.subplots(figsize=(6,6)) # 設置繪圖區域大小

colors = cm.rainbow(np.arange(len(sizes))/len(sizes)) # colormaps: Paired, autumn, rainbow, gray,spring,Darks

patches, texts, autotexts = ax.pie(sizes, labels=labels, autopct='%1.0f%%',

       shadow=False, startangle=170, colors=colors)

ax.axis('equal')  

ax.set_title('Shapes ----', loc='left')

# 重新設置字體大小

proptease = fm.FontProperties()

proptease.set_size('xx-small')

# font size include: 『xx-small』,x-small』,'small』,'medium』,『large』,『x-large』,『xx-large』 or number, e.g. '12'

plt.setp(autotexts, fontproperties=proptease)

plt.setp(texts, fontproperties=proptease)

plt.savefig('Demo_project_set_color_2.jpg')

plt.show()

從上圖可以看出，顏色顯示是連續的，實現了我們想要的效果

3.4 設置圖例（legend）

from matplotlib import font_manager as fm

from  matplotlib import cm

labels = s.index

sizes = s.values

# explode = (0.2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)  # only "explode" the 1st slice

fig, ax = plt.subplots(figsize=(6,6)) # 設置繪圖區域大小

colors = cm.rainbow(np.arange(len(sizes))/len(sizes)) # colormaps: Paired, autumn, rainbow, gray,spring,Darks

patches, texts, autotexts = ax.pie(sizes, labels=labels, autopct='%1.0f%%',

       shadow=False, startangle=170, colors=colors)

ax.axis('equal')  

# 重新設置字體大小

proptease = fm.FontProperties()

proptease.set_size('xx-small')

# font size include: 『xx-small』,x-small』,'small』,'medium』,『large』,『x-large』,『xx-large』 or number, e.g. '12'

plt.setp(autotexts, fontproperties=proptease)

plt.setp(texts, fontproperties=proptease)

ax.legend(labels, loc=2)

plt.savefig('Demo_project_set_legend_error.jpg')

plt.show()

從上面可看出，當類別較多時，圖例（legend）的位置擺放顯示有重疊，顯示有些問題，需要進行調整。

3.5 重新設置圖例（legend）

from matplotlib import font_manager as fm

from  matplotlib import cm

labels = s.index

sizes = s.values

# explode = (0.2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0)  # only "explode" the 1st slice

fig, axes = plt.subplots(figsize=(10,5),ncols=2) # 設置繪圖區域大小

ax1, ax2 = axes.ravel()

colors = cm.rainbow(np.arange(len(sizes))/len(sizes)) # colormaps: Paired, autumn, rainbow, gray,spring,Darks

patches, texts, autotexts = ax1.pie(sizes, labels=labels, autopct='%1.0f%%',

       shadow=False, startangle=170, colors=colors)

ax1.axis('equal')  

# 重新設置字體大小

proptease = fm.FontProperties()

proptease.set_size('xx-small')

# font size include: 『xx-small』,x-small』,'small』,'medium』,『large』,『x-large』,『xx-large』 or number, e.g. '12'

plt.setp(autotexts, fontproperties=proptease)

plt.setp(texts, fontproperties=proptease)

ax1.set_title('Shapes', loc='center')

# ax2 只顯示圖例（legend）

ax2.axis('off')

ax2.legend(patches, labels, loc='center left')

plt.tight_layout()

plt.savefig('Demo_project_set_legend_good.jpg')

plt.show()

3.6 將某些類別突出顯示

將某些類別突出顯示

控制label的顯示位置

控制百分比的顯示位置

控制突出位置的大小

from matplotlib import font_manager as fm

from  matplotlib import cm

labels = s.index

sizes = s.values

explode = (0.1,0,0,0,0,0,0,0,0,0,0,0,0,0.2,0,0,0,0.1,0)  # "explode" ， show the selected slice

fig, axes = plt.subplots(figsize=(8,5),ncols=2) # 設置繪圖區域大小

ax1, ax2 = axes.ravel()

colors = cm.rainbow(np.arange(len(sizes))/len(sizes)) # colormaps: Paired, autumn, rainbow, gray,spring,Darks

patches, texts, autotexts = ax1.pie(sizes, labels=labels, autopct='%1.0f%%',explode=explode,

       shadow=False, startangle=170, colors=colors, labeldistance=1.2,pctdistance=1.03, radius=0.4)

# labeldistance: 控制labels顯示的位置

# pctdistance: 控制百分比顯示的位置

# radius: 控制切片突出的距離

ax1.axis('equal')  

# 重新設置字體大小

proptease = fm.FontProperties()

proptease.set_size('xx-small')

# font size include: 『xx-small』,x-small』,'small』,'medium』,『large』,『x-large』,『xx-large』 or number, e.g. '12'

plt.setp(autotexts, fontproperties=proptease)

plt.setp(texts, fontproperties=proptease)

ax1.set_title('Shapes', loc='center')

# ax2 只顯示圖例（legend）

ax2.axis('off')

ax2.legend(patches, labels, loc='center left')

plt.tight_layout()

# plt.savefig("pie_shape_ufo.png", bbox_inches='tight')

plt.savefig('Demo_project_final.jpg')

plt.show()

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