如何在matplotlib中获取条形图/堆积条形图上的标签?

时间:2016-03-09 01:27:33

标签: python matplotlib plot pyqt bar-chart

我在PyQt Canvas中嵌入了一个非常简单的堆叠matplotlib条形图。我试图根据点击获得条形区域(矩形)的相应标签。但是当我尝试从事件中打印信息时,我总是会得到 _nolegend _ 。理想情况下,我希望在代码中附加条形图上看到相应的标签。

例如,当您点击灰色栏时,它应该打印 a2

import sys
import matplotlib.pyplot as plt

from PyQt4 import QtGui
from matplotlib.figure import Figure
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas


def on_pick(event):
    print event.artist.get_label()

def main():

    app = QtGui.QApplication(sys.argv)

    w = QtGui.QWidget()
    w.resize(640, 480)
    w.setWindowTitle('Pick Test')

    fig = Figure((10.0, 5.0), dpi=100)
    canvas = FigureCanvas(fig)
    canvas.setParent(w)

    axes = fig.add_subplot(111)

    # bind the pick event for canvas
    fig.canvas.mpl_connect('pick_event', on_pick)

    p1 = axes.bar(1,6,picker=2,label='a1')
    p2 = axes.bar(1,2, bottom=6,color='gray',picker=1,label='a2')

    axes.set_ylim(0,10)
    axes.set_xlim(0,5)

    w.show()

    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

Simple stacked bar plot

1 个答案:

答案 0 :(得分:2)

这有点棘手,因为bar是一个复杂的绘图对象,实际上是由多个组件组成的。

您可以使用get_legend_handles_labels获取轴的所有艺术家和标签。然后你可以看看你当前的艺术家属于哪个组。

所以你的回调可能看起来像这样。

def on_pick(event)
    rect = event.artist

    # Get the artists and the labels
    handles,labels = rect.axes.get_legend_handles_labels()

    # Search for your current artist within all plot groups
    label = [label for h,label in zip(handles, labels) if rect in h.get_children()]

    # Should only be one entry but just double check
    if len(label) == 1:
        label = label[0]
    else:
        label = None

    print label