掌握matplotlib：16个绘图实用小技巧

1. 添加标题-title

<code>import numpy as np import matplotlib.pyplot as plt # 显示中文 plt.rcParams['font.sans-serif'] = [u'SimHei'] plt.rcParams['axes.unicode_minus'] = False %matplotlib inline x = np.arange(0, 10) plt.title('示例标题') plt.plot(x, x*x) plt.show()</code>

2. 添加文字-text

<code>import numpy as np import matplotlib.pyplot as plt # 显示中文 plt.rcParams['font.sans-serif'] = [u'SimHei'] plt.rcParams['axes.unicode_minus'] = False %matplotlib inline x = np.arange(-10, 11, 1) y = x*x plt.plot(x, y) plt.title('示例标题') # 添加文字 plt.text(-2.5, 30, 'function y=x*x') plt.show()</code>

3. 添加注释-annotate

<code>import numpy as np import matplotlib.pyplot as plt # 显示中文 plt.rcParams['font.sans-serif'] = [u'SimHei'] plt.rcParams['axes.unicode_minus'] = False %matplotlib inline x = np.arange(-10, 11, 1) y = x*x plt.title('示例标题') plt.plot(x, y) # 添加注释 plt.annotate('示例注释', xy=(0, 1), xytext=(-2, 22), arrowprops={'headwidth': 10, 'facecolor': 'r'}) plt.show()</code>

4. 设置坐标轴名称-xlabel/ylabel

<code>import numpy as np import matplotlib.pyplot as plt # 显示中文 plt.rcParams['font.sans-serif'] = [u'SimHei'] plt.rcParams['axes.unicode_minus'] = False %matplotlib inline x = np.arange(1, 20) plt.xlabel('示例x轴') plt.ylabel('示例y轴') plt.plot(x, x*x) plt.show()</code>

5. 添加图例-legend

<code>import numpy as np import matplotlib.pyplot as plt # 显示中文 plt.rcParams['font.sans-serif'] = [u'SimHei'] plt.rcParams['axes.unicode_minus'] = False %matplotlib inline x = np.arange(1, 20) plt.plot(x, x) plt.plot(x, x*2) plt.plot(x, x*3) plt.plot(x, x*4) # 直接传入legend plt.legend(['生活', '颜值', '工作', '金钱']) plt.show()</code>

6. 调整颜色-color

<code>import numpy as np import matplotlib.pyplot as plt %matplotlib inline x = np.arange(1, 5) # 颜色的几种方式 plt.plot(x, color='g') plt.plot(x+1, color='0.5') plt.plot(x+2, color='#FF00FF') plt.plot(x+3, color=(0.1, 0.2, 0.3)) plt.show()</code>

7. 切换线条样式-marker

<code>import numpy as np import matplotlib.pyplot as plt %matplotlib inline x = np.arange(1, 5) plt.plot(x, marker='o') plt.plot(x+1, marker='>') plt.plot(x+2, marker='s') plt.show()</code>

8. 显示数学公式-mathtext

<code>import numpy as np import matplotlib.pyplot as plt %matplotlib inline plt.title('示例标题') plt.xlim([1, 8]) plt.ylim([1, 5]) plt.text(2, 4, r'$ \alpha \beta \pi \lambda \omega $', size=25) plt.text(4, 4, r'$ \sin(0)=\cos(\frac{\pi}{2}) $', size=25) plt.text(2, 2, r'$ \lim_{x \rightarrow y} \frac{1}{x^3} $', size=25) plt.text(4, 2, r'$ \sqrt[4]{x}=\sqrt{y} $', size=25) plt.show()</code>

9. 显示网格-grid

<code>import numpy as np import matplotlib.pyplot as plt %matplotlib inline x = ['a', 'b', 'c', 'd'] y = [15, 30, 45, 10] plt.grid() # 也可以设置颜色、线条宽度、线条样式 # plt.grid(color='g', linewidth='1', linestyle='-.') plt.plot(x, y) plt.show()</code>

10. 调整坐标轴刻度-locator_params

<code>import numpy as np import matplotlib.pyplot as plt %matplotlib inline x = np.arange(0, 30, 1) plt.plot(x, x) # x轴和y轴分别显示20个 plt.locator_params(nbins=20) plt.show()</code>

11. 调整坐标轴范围-axis/xlim/ylim

<code>import numpy as np import matplotlib.pyplot as plt %matplotlib inline x = np.arange(0, 30, 1) plt.plot(x, x*x) # 调整x为10到25 plt.xlim(xmin=10, xmax=25) plt.plot(x, x*x) plt.show()</code>

12. 调整日期自适应-autofmt_xdate

<code>import numpy as np import pandas as pd import matplotlib.pyplot as plt %matplotlib inline x = pd.date_range('2020/01/01', periods=30) y = np.arange(0, 30, 1) plt.plot(x, y) plt.gcf().autofmt_xdate() plt.show()</code>

13. 添加双坐标轴-twinx

<code>import numpy as np import matplotlib.pyplot as plt %matplotlib inline x = np.arange(1, 20) y1 = x*x y2 = np.log(x) plt.plot(x, y1) # 添加一个坐标轴，默认0到1 plt.twinx() plt.plot(x, y2, 'r') plt.show()</code>

14. 填充区域-fill/fill_beween

<code>import numpy as np import matplotlib.pyplot as plt %matplotlib inline x = np.linspace(0, 5*np.pi, 1000) y1 = np.sin(x) y2 = np.sin(2*x) plt.plot(x, y1) plt.plot(x, y2) # 填充 plt.fill(x, y1, 'g') plt.fill(x, y2, 'r') plt.title('示例标题') plt.show()</code>

<code>import numpy as np import matplotlib.pyplot as plt %matplotlib inline x = np.linspace(0, 5*np.pi, 1000) y1 = np.sin(x) y2 = np.sin(2*x) plt.plot(x, y1) plt.plot(x, y2) # 填充 plt.fill_between(x, y1, y2, where=y1>y2, interpolate=True) plt.show()</code>

15. 画一个填充好的形状-matplotlib.patche

<code>import numpy as np import matplotlib.pyplot as plt import matplotlib.patches as mptaches %matplotlib inline xy1 = np.array([0.2, 0.2]) xy2 = np.array([0.2, 0.8]) xy3 = np.array([0.8, 0.2]) xy4 = np.array([0.8, 0.8]) fig, ax = plt.subplots() # 圆形,指定坐标和半径 circle = mptaches.Circle(xy1, 0.15) ax.add_patch(circle) # 长方形 rect = mptaches.Rectangle(xy2, 0.2, 0.1, color='r') ax.add_patch(rect) # 多边形 polygon = mptaches.RegularPolygon(xy3, 6, 0.1, color='g') ax.add_patch(polygon) # 椭圆 ellipse = mptaches.Ellipse(xy4, 0.4, 0.2, color='c') ax.add_patch(ellipse) ax.axis('equal') plt.show()</code>

16. 切换样式-plt.style.use

<code>import matplotlib.pyplot as plt plt.style.available</code>

<code>import matplotlib.pyplot as plt plt.style.use('ggplot') # 新建4个子图 fig, axes = plt.subplots(2, 2) ax1, ax2, ax3, ax4 = axes.ravel() # 第一个图 x, y = np.random.normal(size=(2, 100)) ax1.plot(x, y, 'o') # 第二个图 x = np.arange(0, 10) y = np.arange(0, 10) colors = plt.rcParams['axes.prop_cycle'] length = np.linspace(0, 10, len(colors)) for s in length: ax2.plot(x, y+s, '-') # 第三个图 x = np.arange(5) y1, y2, y3 = np.random.randint(1, 25, size=(3, 5)) width = 0.25 ax3.bar(x, y1, width) ax3.bar(x+width, y2, width) ax3.bar(x+2*width, y3, width) # 第四个图 for i, color in enumerate(colors): xy = np.random.normal(size=2) ax4.add_patch(plt.Circle(xy, radius=0.3, color=color['color'])) ax4.axis('equal') plt.show()</code>