PyQtGraph - 获取误差条形图的坐标值

在本文中，我们将看到如何在 PyQtGraph 模块中获取误差条形图的坐标值。 PyQtGraph 是一个用于Python的图形和用户界面库，它提供了设计和科学应用程序中通常需要的功能。它的主要目标是提供用于显示数据（绘图、视频等）的快速交互式图形。误差条是数据可变性的图形表示，并在图表上用于指示报告测量中的误差或不确定性。它们给出了测量精确度的一般概念，或者相反，真实值可能与报告值相差多远。误差棒图的坐标值是x、y坐标，可以借助setX和setY方法进行设置。
我们可以在下面给出的命令的帮助下创建一个绘图窗口并在其上创建一个误差条形图。

# creating a pyqtgraph plot window
plt = pg.plot()

# creating a error bar item object
error = pg.ErrorBarItem(x=x, y=y, top=top, 
                   bottom=bottom, beam=0.5)

In order to do this we use x and y method with the error bar item object
Syntax : error.x() and error.y() 
Argument : It takes no argument
Return : It returns float value 

下面是实现。

Python3

# importing Qt widgets
from PyQt5.QtWidgets import *
  
# importing system
import sys
  
# importing numpy as np
import numpy as np
  
# importing pyqtgraph as pg
import pyqtgraph as pg
from PyQt5.QtGui import *
from PyQt5.QtCore import *
  
from collections import namedtuple
  
  
class Window(QMainWindow):
  
    def __init__(self):
        super().__init__()
  
        # setting title
        self.setWindowTitle("PyQtGraph")
  
        # setting geometry
        self.setGeometry(100, 100, 600, 500)
  
        # icon
        icon = QIcon("skin.png")
  
        # setting icon to the window
        self.setWindowIcon(icon)
  
        # calling method
        self.UiComponents()
  
        # showing all the widgets
        self.show()
  
    # method for components
    def UiComponents(self):
  
        # creating a widget object
        widget = QWidget()
  
        # creating a label
        label = QLabel("Geeksforgeeks Error Bar plot")
  
        # setting minimum width
        label.setMinimumWidth(130)
  
        # making label do word wrap
        label.setWordWrap(True)
  
        # setting configuration options
        pg.setConfigOptions(antialias=True)
  
        # creating x-axis values
        x = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
  
        # creating y-axis values
        y = np.array([5, 4, 3, 2, 5, 6, 4, 8, 9, 8])
  
        # creating upper bound values
        top = np.array([2, 2, 2, 2, 2, 2, 2, 2, 2, 2])
  
        # creating lower bound values
        bottom = np.array([2, 2, 2, 2, 2, 2, 2, 2, 2, 2])
  
        # creating a plot window
        plt = pg.plot()
  
        # creating a error bar item
        error = pg.ErrorBarItem(beam=0.5)
  
        # setting data to error bar item
        error.setData(x=x, y=y, top=top, bottom=bottom)
  
        # adding error bar item to the plot window
        plt.addItem(error)
  
        # plotting the data on plot window
        plt.plot(x, y, symbol='o', pen={'color': 0.8, 'width': 2})
  
        # Creating a grid layout
        layout = QGridLayout()
  
        # minimum width value of the label
        label.setMinimumWidth(130)
  
        # setting this layout to the widget
        widget.setLayout(layout)
  
        # adding label in the layout
        layout.addWidget(label, 1, 0)
  
        # plot window goes on right side, spanning 3 rows
        layout.addWidget(plt, 0, 1, 3, 1)
  
        # setting this widget as central widget of the main widow
        self.setCentralWidget(widget)
  
        error.setX(0.5)
  
        # getting x-co-ordinate of error bar item
        value = error.x()
  
        # setting text to the label
        label.setText("X-Coordinate : " + str(value))
  
  
# create pyqt5 app
App = QApplication(sys.argv)
  
# create the instance of our Window
window = Window()
  
# start the app
sys.exit(App.exec())

输出 ：