使用matplotlib在python中画图

$ sudo apt-get install ipython python-matplotlib python-numpy

>>> plt.figure(1)                              # 创建图表1
<matplotlib.figure.Figure object at 0x26fda10>
>>> plt.figure(2)                              # 创建图表2
<matplotlib.figure.Figure object at 0x2a5f610>
>>> ax1 = plt.subplot(211)                     # 在图表2中创建子图1
>>> ax2 = plt.subplot(212)                     # 在图表2中创建子图2
>>> x = np.linspace(0, 3, 100)
>>> plt.figure(1)                              # 选择图表1
<matplotlib.figure.Figure object at 0x26fda10>
>>> plt.plot(x, np.exp(x/3))
[<matplotlib.lines.Line2D object at 0x36383d0>]
>>> plt.sca(ax1)                               # 选择图表2的子图1
>>> plt.plot(x, np.sin(x))
[<matplotlib.lines.Line2D object at 0x3638890>]
>>> plt.sca(ax2)                               # 选择图表2的子图2
>>> plt.plot(x, np.sin(2*x))
[<matplotlib.lines.Line2D object at 0x3638dd0>]
>>> plt.show()