为什么我的折线图不显示在GUI上

Question

This is a function which is being called on a button click. It is supposed to display a line graph why is it not showing up.

def plotk2(self):
#----------------------------------------------------------------Data
    temp=full_dataset[['country_txt','iyear','nkill']]
    text = self.k_count.currentText()
    temp = temp[temp['country_txt'].str.match(text)]
    temp2=temp.groupby(['iyear'])['nkill'].count()
    temp2=temp2.to_frame()
    temp2['iyear']=temp2.index
#----------------------------------------------------------------
    self.figure.clear()

    ax = self.figure.add_subplot(111)
    plt.plot( 'nkill', 'iyear', data=temp2)
    #ax.axis('off')


    plt.show()

    self.canvas.draw()

Answer 1

If you want to draw on PyQt you must use FigureCanvas , not matplotlib.pyplot , so if you use plt.plot() you will not draw anything.

In your case a similar example would be:

import sys
import pandas as pd

import matplotlib
matplotlib.use('Qt5Agg')
from PyQt5 import QtCore, QtWidgets
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure

class Widget(QtWidgets.QWidget):
    def __init__(self, *args, **kwargs):
        QtWidgets.QWidget.__init__(self, *args, **kwargs)
        self.figure = Figure(figsize=(5, 4), dpi=100)
        self.canvas = FigureCanvas(self.figure)
        self.canvas.setSizePolicy(QtWidgets.QSizePolicy.Expanding, QtWidgets.QSizePolicy.Expanding)

        button = QtWidgets.QPushButton("random plot")
        button.clicked.connect(self.plot)

        lay = QtWidgets.QVBoxLayout(self)
        lay.addWidget(self.canvas)
        lay.addWidget(button)
        self.plot()

    def plot(self):
        self.figure.clear()
        ax = self.figure.add_subplot(111)
        d = {'nkill': [1, 2, 4, 5, 6], 'iyear': [3, 4, 5, 5, 5]}
        df = pd.DataFrame(data=d)
        ax.plot('nkill', 'iyear', data=df)
        # ax.axis('off')
        self.canvas.draw()

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())