matplotlib & pandas

Python/matplotlab/gallery/widgets/span_selector.md

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+# 跨度选择器
+
+SpanSelector是一个鼠标小部件，用于选择xmin / xmax范围并绘制下轴中所选区域的详细视图
+
+![跨度选择器示例](https://matplotlib.org/_images/sphx_glr_span_selector_001.png)
+
+```python
+import numpy as np
+import matplotlib.pyplot as plt
+from matplotlib.widgets import SpanSelector
+
+# Fixing random state for reproducibility
+np.random.seed(19680801)
+
+fig, (ax1, ax2) = plt.subplots(2, figsize=(8, 6))
+ax1.set(facecolor='#FFFFCC')
+
+x = np.arange(0.0, 5.0, 0.01)
+y = np.sin(2*np.pi*x) + 0.5*np.random.randn(len(x))
+
+ax1.plot(x, y, '-')
+ax1.set_ylim(-2, 2)
+ax1.set_title('Press left mouse button and drag to test')
+
+ax2.set(facecolor='#FFFFCC')
+line2, = ax2.plot(x, y, '-')
+
+
+def onselect(xmin, xmax):
+    indmin, indmax = np.searchsorted(x, (xmin, xmax))
+    indmax = min(len(x) - 1, indmax)
+
+    thisx = x[indmin:indmax]
+    thisy = y[indmin:indmax]
+    line2.set_data(thisx, thisy)
+    ax2.set_xlim(thisx[0], thisx[-1])
+    ax2.set_ylim(thisy.min(), thisy.max())
+    fig.canvas.draw()
+
+# Set useblit=True on most backends for enhanced performance.
+span = SpanSelector(ax1, onselect, 'horizontal', useblit=True,
+                    rectprops=dict(alpha=0.5, facecolor='red'))
+
+
+plt.show()
+```
+
+## 下载这个示例
+            
+- [下载python源码: span_selector.py](https://matplotlib.org/_downloads/span_selector.py)
+- [下载Jupyter notebook: span_selector.ipynb](https://matplotlib.org/_downloads/span_selector.ipynb)