套索选择器演示

使用套索工具以交互方式选择数据点。

此示例绘制散点图。 然后，您可以通过在图表上的点周围绘制套索循环来选择几个点。 要绘制，只需单击图形，按住，然后将其拖动到需要选择的点周围。

  1. import numpy as np
  3. from matplotlib.widgets import LassoSelector
  4. from matplotlib.path import Path
  7. class SelectFromCollection(object):
  8.     """Select indices from a matplotlib collection using `LassoSelector`.
  10.     Selected indices are saved in the `ind` attribute. This tool fades out the
  11.     points that are not part of the selection (i.e., reduces their alpha
  12.     values). If your collection has alpha < 1, this tool will permanently
  13.     alter the alpha values.
  15.     Note that this tool selects collection objects based on their *origins*
  16.     (i.e., `offsets`).
  18.     Parameters
  19.     ----------
  20.     ax : :class:`~matplotlib.axes.Axes`
  21.         Axes to interact with.
  23.     collection : :class:`matplotlib.collections.Collection` subclass
  24.         Collection you want to select from.
  26.     alpha_other : 0 <= float <= 1
  27.         To highlight a selection, this tool sets all selected points to an
  28.         alpha value of 1 and non-selected points to `alpha_other`.
  29.     """
  31.     def __init__(self, ax, collection, alpha_other=0.3):
  32.         self.canvas = ax.figure.canvas
  33.         self.collection = collection
  34.         self.alpha_other = alpha_other
  36.         self.xys = collection.get_offsets()
  37.         self.Npts = len(self.xys)
  39.         # Ensure that we have separate colors for each object
  40.         self.fc = collection.get_facecolors()
  41.         if len(self.fc) == 0:
  42.             raise ValueError('Collection must have a facecolor')
  43.         elif len(self.fc) == 1:
  44.             self.fc = np.tile(self.fc, (self.Npts, 1))
  46.         self.lasso = LassoSelector(ax, onselect=self.onselect)
  47.         self.ind = []
  49.     def onselect(self, verts):
  50.         path = Path(verts)
  51.         self.ind = np.nonzero(path.contains_points(self.xys))[0]
  52.         self.fc[:, -1] = self.alpha_other
  53.         self.fc[self.ind, -1] = 1
  54.         self.collection.set_facecolors(self.fc)
  55.         self.canvas.draw_idle()
  57.     def disconnect(self):
  58.         self.lasso.disconnect_events()
  59.         self.fc[:, -1] = 1
  60.         self.collection.set_facecolors(self.fc)
  61.         self.canvas.draw_idle()
  64. if __name__ == '__main__':
  65.     import matplotlib.pyplot as plt
  67.     # Fixing random state for reproducibility
  68.     np.random.seed(19680801)
  70.     data = np.random.rand(100, 2)
  72.     subplot_kw = dict(xlim=(0, 1), ylim=(0, 1), autoscale_on=False)
  73.     fig, ax = plt.subplots(subplot_kw=subplot_kw)
  75.     pts = ax.scatter(data[:, 0], data[:, 1], s=80)
  76.     selector = SelectFromCollection(ax, pts)
  78.     def accept(event):
  79.         if event.key == "enter":
  80.             print("Selected points:")
  81.             print(selector.xys[selector.ind])
  82.             selector.disconnect()
  83.             ax.set_title("")
  84.             fig.canvas.draw()
  86.     fig.canvas.mpl_connect("key_press_event", accept)
  87.     ax.set_title("Press enter to accept selected points.")
  89.     plt.show()

下载这个示例