Question

我正在尝试使用matplotlib LassoSelector从散点图中选择一些点，并仅为选定点生成单独的图形。当我尝试在第二个图上使用另一个matplotlib小部件时，它不起作用，但没有错误或警告消息。下面是使用LassoSelector和SpanSelector的最小示例。

我也尝试过其他小部件; Button小部件显示按钮，但不按下按钮上的操作。

import numpy as np
from matplotlib.pyplot import *
from matplotlib.widgets import SpanSelector, LassoSelector
from matplotlib.path import Path

def onselect(verts):
    global xys,data

    #get indexes of selected points
    path = Path(verts)
    xysn = xys.get_offsets()
    ind = np.nonzero([path.contains_point(xy) for xy in xysn])[0]

    #plot the second figure
    fig=figure(2)
    ax=fig.add_subplot(111)
    ax.hist(data[:,0][ind],10)

    #this should be executed when SpanSelector is used
    def action(min,max):
        print min,max

    #try to do SpanSelector (this fails)
    span=SpanSelector(ax,action,'horizontal')

    show()

#initialize a figure
fig=figure(1)
ax=fig.add_subplot(111)

#create data
data=np.array([[1,6], [4,8],[0,4],[4,2],[9,6],[10,8],[2,2],[5,5],[0,4],[4,5]])

#plot data
xys=ax.scatter(data[:,0],data[:,1])

#select point by drawing a path around them
lasso = LassoSelector(ax, onselect=onselect)

show()

Answer 1

matplotlib小部件是事件驱动的，因此请等待用户输入。您的代码问题是您正在尝试使用新的事件处理程序SpanSelector创建新图形。我不确定您是否可以添加以前的新事件并且SpanSelector已注释掉，我收到以下错误，

QCoreApplication::exec: The event loop is already running

因此，新事件LassoSelector未注册，用户输入未被提取（并且新数字不会出现）。最好创建所有数字并在代码开头注册所有可能的事件。以下内容应该更接近您想要做的事情，

import numpy as np
from matplotlib.pyplot import *
from matplotlib.widgets import SpanSelector, LassoSelector
from matplotlib.path import Path

#this should be executed when LassoSelector is used
def onselect(verts):
    global xys,data

    #get indexes of selected points
    path = Path(verts)
    xysn = xys.get_offsets()
    ind = np.nonzero([path.contains_point(xy) for xy in xysn])[0]

    #Clear and update bar chart
    h, b = np.histogram(data[:,0][ind],10)
    for rect, bars in zip(rects, h):
        rect.set_height(bars)
    ax2.bar(mb, h, align='center')
    draw()

#this should be executed when SpanSelector is used
def action(min,max):
    print min,max

#initialize figures
fig1=figure(1)
ax1=fig1.add_subplot(111)

fig2=figure(2)
ax2=fig2.add_subplot(111)

#create data
data=np.array([[1,6],[4,8],[0,4],[4,2],[9,6],[10,8],[2,2],[5,5],[0,4],[4,5]])

#plot data
xys=ax1.scatter(data[:,0],data[:,1])

#Plot initial histogram of all data
h, b = np.histogram(data[:,0],10)
mb = [0.5*(b[i]+b[i+1]) for i in range(b.shape[0]-1)]
rects = ax2.bar(mb, h, align='center')

#Register lasso selector
lasso = LassoSelector(ax1, onselect=onselect)

#Register SpanSelector 
span=SpanSelector(ax2,action,'horizontal')

show()

注意，为了更新条形图，它比绘图更棘手，所以我在这里使用了这个答案Dynamically updating a bar plot in matplotlib

由于某种原因，直方图图2仅在您单击时更新。我会考虑使用带有两个轴的单个图形，这可能更容易使用，

fig, ax = subplots(2,1)
ax1 = ax[0]; ax2 = ax[1]

Matplotlib小部件用于另一个matplotlib小部件生成的绘图

1 个答案: