Question

我是matplotlib的新手，这里是情况简化情节的图片： http://postimg.org/image/qkdm6p31p/

我想为某个阈值以上的值设置一个红色标记，在这种情况下，红线上方的两个点有一个红色标记。在matplotlib中可以吗？

当我关闭窗口时，我真的不明白为什么我的代码永远不会完成执行。

这是我的代码：

import wx
import numpy as np
import matplotlib
matplotlib.use('WXAgg')
import matplotlib.pyplot as plt
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as FigureCanvas

class GraphFrame(wx.Frame):

    def __init__(self):
        self.displaySize = wx.DisplaySize() 
        wx.Frame.__init__(self, None, -1,
                 style = wx.DEFAULT_FRAME_STYLE,
                 size = (self.displaySize[0], self.displaySize[1]))
        self.threshold = 3000
        self.create_main_panel()
        self.draw_plot()

    def create_main_panel(self):
        self.panel = wx.Panel(self,-1, style = wx.SUNKEN_BORDER)
        self.fig = plt.figure()
        self.canvas = FigureCanvas(self.panel, -1, self.fig)

        self.panelsizer = wx.BoxSizer(wx.HORIZONTAL)
        self.panelsizer.Add(self.canvas, 1, wx.EXPAND)        
        self.panel.SetSizer(self.panelsizer)
        mainsizer = wx.BoxSizer(wx.VERTICAL)
        mainsizer.Add(self.panel, 1, wx.EXPAND )        
    self.SetSizerAndFit(mainsizer)

        self.init_plot()

    def init_plot(self):
        self.axes = self.fig.add_subplot(111)
        self.axes.set_axis_bgcolor('white')
        self.axes.set_title('TITLE', size=12)
        self.data = ['2000','2869','4694','2356','3600','1500']
    self.xmin = 0
    self.xmax = len(self.data)

    def draw_plot(self):
        self.plot_data = self.axes.plot(
          self.data, 
          linewidth=3,
          label = "plot1",
          marker = "o",
          markersize =7,
          )[0]
        self.plot_data.set_xdata(np.arange(len(self.data)))
        self.plot_data.set_ydata(np.array(self.data))
        thresholdplot = self.axes.plot([self.xmin,self.xmax], [self.threshold,self.threshold],"r--",label = "threshold",linewidth = 1)
        lg=self.axes.legend(loc="upper left", bbox_to_anchor=(1,1),ncol=1)
        self.canvas.draw()

if __name__ == "__main__":   
  app = wx.PySimpleApp()
  app.frame = GraphFrame()
  app.frame.Show()
  app.MainLoop()
  print "Finished"

我正在使用Matplotlib，wx和Python 2.7 真的很感谢你的帮助。

Answer 1

实现此效果的最简单方法可能是简单地绘制第二次大于阈值的数据子集。例如：

import matplotlib.pyplot as plt
import numpy as np

fig, ax = plt.subplots()

ys = np.random.rand(10)

threshold = 0.5

ax.axhline(y=threshold, color='r', linestyle=':')
ax.plot(ys)

greater_than_threshold = [i for i, val in enumerate(ys) if val>threshold]
ax.plot(greater_than_threshold, ys[greater_than_threshold], 
        linestyle='none', color='r', marker='o')

plt.show()

matplotlib：值超过阈值时的不同标记颜色

1 个答案: