如何在轴上绘制时间图

Question

我正在尝试编写一些代码来实时绘制一些值，我发现下面的示例并且它有效，但我想在轴 12:30:20、12:30:21 上显示时间... .. 而不是显示 10、20、30。

是否有任何解决方案或我可以在哪里阅读？

import sys
import random
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 MplCanvas(FigureCanvas):

    def __init__(self, parent=None, width=5, height=4, dpi=100):
        fig = Figure(figsize=(width, height), dpi=dpi)
        self.axes = fig.add_subplot(111)
        super(MplCanvas, self).__init__(fig)


class MainWindow(QtWidgets.QMainWindow):

    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        self.canvas = MplCanvas(self, width=5, height=4, dpi=100)
        self.setCentralWidget(self.canvas)

        n_data = 50
        self.xdata = list(range(n_data))
        self.ydata = [random.randint(0, 10) for i in range(n_data)]
        self.update_plot()

        self.show()

        # Setup a timer to trigger the redraw by calling update_plot.
        self.timer = QtCore.QTimer()
        self.timer.setInterval(100)
        self.timer.timeout.connect(self.update_plot)
        self.timer.start()

    def update_plot(self):
        # Drop off the first y element, append a new one.
        self.ydata = self.ydata[1:] + [random.randint(0, 10)]
        self.canvas.axes.cla()  # Clear the canvas.
        self.canvas.axes.plot(self.xdata, self.ydata, 'r')
        # Trigger the canvas to update and redraw.
        self.canvas.draw()


app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
app.exec_()

Answer 1

您可以在 xdata 上设置您想要的值，如下所示：

import sys
import random
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 MplCanvas(FigureCanvas):
    def __init__(self, parent=None, width=5, height=4, dpi=100):
        fig = Figure(figsize=(width, height), dpi=dpi)
        self.axes = fig.add_subplot(111)
        super(MplCanvas, self).__init__(fig)

class MainWindow(QtWidgets.QMainWindow):
    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        self.canvas = MplCanvas(self, width=5, height=4, dpi=100)
        self.setCentralWidget(self.canvas)

        self.xdata = ["12:30:20", "12:30:21", "12:30:22", "12:30:23", "12:30:24"]
        self.ydata = [random.randint(0, 10) for i in self.xdata]
        self.update_plot()

        self.show()

        # Setup a timer to trigger the redraw by calling update_plot.
        self.timer = QtCore.QTimer()
        self.timer.setInterval(500)
        self.timer.timeout.connect(self.update_plot)
        self.timer.start()

    def update_plot(self):
        # Drop off the first y element, append a new one.
        self.ydata = self.ydata[1:] + [random.randint(0, 10)]
        self.canvas.axes.cla()  # Clear the canvas.
        self.canvas.axes.plot(self.xdata, self.ydata, 'r')
        # Trigger the canvas to update and redraw.
        self.canvas.draw()


app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
app.exec_()

会产生这个：

您可以在那里使用任何您想要的值，这是另一个带有字母的示例：

        self.xdata = ["aa", "bb", "cc", "dd", "ee"]
        self.ydata = [random.randint(0, 10) for i in self.xdata]

这是评论中后续问题的一个版本。
如果您希望 xdata 发生变化，您需要对 ydata

做同样的事情

import sys
import random
import datetime
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 MplCanvas(FigureCanvas):
    def __init__(self, parent=None, width=5, height=4, dpi=100):
        fig = Figure(figsize=(width, height), dpi=dpi)
        self.axes = fig.add_subplot(111)
        super(MplCanvas, self).__init__(fig)


class MainWindow(QtWidgets.QMainWindow):
    def now(self, x):
        n = datetime.datetime.now()
        return (n + datetime.timedelta(seconds=x)).strftime("%H:%M:%S")

    def __init__(self, *args, **kwargs):
        super(MainWindow, self).__init__(*args, **kwargs)

        self.canvas = MplCanvas(self, width=5, height=4, dpi=100)
        self.setCentralWidget(self.canvas)

        self.xdata = [self.now(-5), self.now(-4), self.now(-3), self.now(-2), self.now(-1)]
        self.ydata = [random.randint(0, 10) for i in self.xdata]
        self.update_plot()
        self.show()

        # Setup a timer to trigger the redraw by calling update_plot.
        self.timer = QtCore.QTimer()
        self.timer.setInterval(1000)
        self.timer.timeout.connect(self.update_plot)
        self.timer.start()

    def update_plot(self):
        # Drop off the first element, append a new one.
        self.xdata = self.xdata[1:] + [self.now(0)]
        self.ydata = self.ydata[1:] + [random.randint(0, 10)]
        self.canvas.axes.cla()  # Clear the canvas.
        self.canvas.axes.plot(self.xdata, self.ydata, 'r')
        # Trigger the canvas to update and redraw.
        self.canvas.draw()


app = QtWidgets.QApplication(sys.argv)
w = MainWindow()
app.exec_()

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