python数据可视化——matplotlib 用户手册入门：pyplot 画图

参考matplotlib官方指南：

https://matplotlib.org/tutorials/introductory/pyplot.html#sphx-glr-tutorials-introductory-pyplot-py

pyplot是常用的画图模块，功能非常强大，下面就来见识下它的能力吧

1.快速画出常见图形

2.使用关键字字符串作图

3.使用类别变量画图

4.创建多图

 import matplotlib.pyplot as plt
 %matplotlib inline
 plt.figure(1)                # the first figure
 plt.subplot(211)             # the first subplot in the first figure
 plt.plot([1, 2, 3])
 plt.subplot(212)             # the second subplot in the first figure
 plt.plot([4, 5, 6])

 plt.figure(2)                # a second figure
 plt.plot([4, 5, 6])          # creates a subplot(111) by default

 plt.figure(1)                # figure 1 current; subplot(212) still current
 plt.subplot(211)             # make subplot(211) in figure1 current
 plt.title('Easy as 1, 2, 3') # subplot 211 title

 import matplotlib.pyplot as plt
 import numpy as np

 np.random.seed(19680801)
 data = np.random.randn(2, 100)

 fig, axs = plt.subplots(2, 2, figsize=(5, 5))
 axs[0, 0].hist(data[0])
 axs[1, 0].scatter(data[0], data[1])
 axs[0, 1].plot(data[0], data[1])
 axs[1, 1].hist2d(data[0], data[1])

 plt.show()

5.添加文本：轴线标签，属性标签

 import matplotlib.pyplot as plt
 import numpy as np
 mu, sigma = 100, 15
 x = mu + sigma * np.random.randn(10000)

 # the histogram of the data
 n, bins, patches = plt.hist(x, 50, normed=True, facecolor='g', alpha=0.75)

 plt.xlabel('Smarts')
 plt.ylabel('Probability')
 plt.title('Histogram of IQ')
 plt.text(60, .025, r'$\mu=100,\ \sigma=15$')   # 支持 LaTex格式
 plt.axis([40, 160, 0, 0.03])
 plt.grid(True)
 plt.show()