In this article, we will see how we can get the position of the error bar graph in the PyQtGraph module. PyQtGraph is a graphics and user interface library for Python that provides functionality commonly required in designing and science applications. Its primary goals are to provide fast, interactive graphics for displaying data (plots, video, etc.). Error bars are graphical representations of the variability of data and used on graphs to indicate the error or uncertainty in a reported measurement. They give a general idea of how precise a measurement is, or conversely, how far from the reported value the true value might be. The position of the error bar item is basically the position of the data from the origin which is by default 0, 0 although it can be changed any time. Changing position does not change the position of line graph data only change the position of error bar graph data. It can be set with the help of setPos() method.
We can create a plot window and create an error bar graph on it with the help of commands given below
# 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 pos() method with the error bar item object
Syntax : error.pos()
Argument : It takes no argument
Return : It returns tuple
Below is the implementation
# 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 window
self .setCentralWidget(widget)
# setting position of the error bar item
error.setPos( 10 , 10 )
# getting position of the error bar item
value = error.pos()
# setting text to the label
label.setText( "Position : " + str (value))
# create pyqt5 app App = QApplication(sys.argv)
# create the instance of our Window window = Window()
# start the app sys.exit(App. exec ())
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Output :