matplotlib & pandas

Python/matplotlab/gallery/scales/log_demo.md

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+# 对数演示
+
+具有对数轴的图的示例。
+
+![对数演示](https://matplotlib.org/_images/sphx_glr_log_demo_001.png)
+
+```python
+import numpy as np
+import matplotlib.pyplot as plt
+
+# Data for plotting
+t = np.arange(0.01, 20.0, 0.01)
+
+# Create figure
+fig, ((ax1, ax2), (ax3, ax4)) = plt.subplots(2, 2)
+
+# log y axis
+ax1.semilogy(t, np.exp(-t / 5.0))
+ax1.set(title='semilogy')
+ax1.grid()
+
+# log x axis
+ax2.semilogx(t, np.sin(2 * np.pi * t))
+ax2.set(title='semilogx')
+ax2.grid()
+
+# log x and y axis
+ax3.loglog(t, 20 * np.exp(-t / 10.0), basex=2)
+ax3.set(title='loglog base 2 on x')
+ax3.grid()
+
+# With errorbars: clip non-positive values
+# Use new data for plotting
+x = 10.0**np.linspace(0.0, 2.0, 20)
+y = x**2.0
+
+ax4.set_xscale("log", nonposx='clip')
+ax4.set_yscale("log", nonposy='clip')
+ax4.set(title='Errorbars go negative')
+ax4.errorbar(x, y, xerr=0.1 * x, yerr=5.0 + 0.75 * y)
+# ylim must be set after errorbar to allow errorbar to autoscale limits
+ax4.set_ylim(bottom=0.1)
+
+fig.tight_layout()
+plt.show()
+```
+
+## 下载这个示例
+            
+- [下载python源码: log_demo.py](https://matplotlib.org/_downloads/log_demo.py)
+- [下载Jupyter notebook: log_demo.ipynb](https://matplotlib.org/_downloads/log_demo.ipynb)