In this article we will see how we can make a PyQt5 application which will visualize the linear search algorithm. Linear search or sequential search is a method for finding an element within a list. It sequentially checks each element of the list until a match is found or the whole list has been searched.
Gui implementation steps : 1. Create a list of label according to the given list of numbers 2. Set their text, border, color and geometry with the respective gap from each other 3. Each label height should be proportional to the value of each number 4. Create a start and pause push button to start the searching and pause the searching 5. Create a result label to show the searching status Back end implementation steps : 1. Create label list corresponding to the given numbers 2. Create a variable to count the index and flag for searching 3. Add action to the push button their action should change the flag status i.e start action should make flag true and pause action should make flag false 4. Create a timer object which calls a method after every specific time 5. Inside the timer method check for the flag is flag is true begin the linear search algorithm 6. If label value if not equal make its color grey then check for next, if value got found make label color green and stop the search and show the output in the result label. 7. If the index counter becomes equal to the list length stop the search and show result as not found.
Below is the implementation
Python3
# importing libraries from PyQt5.QtWidgets import * from PyQt5 import QtCore, QtGui from PyQt5.QtGui import * from PyQt5.QtCore import * import sys class Window(QMainWindow): # list of numbers number = [ 2 , 3 , 6 , 9 , 8 , 12 , 16 , 7 , 10 , 5 , 4 , 11 , 2 , 13 ] def __init__( self ): super ().__init__() # setting title self .setWindowTitle("Linear search ") # setting geometry self .setGeometry( 100 , 100 , 600 , 400 ) # calling method self .UiComponents() # showing all the widgets self .show() # method for widgets def UiComponents( self ): # start flag self .start = False # list to hold labels self .label_list = [] # desired value self .desired = 11 # counter for keeping index self .counter = 0 # local counter c = 0 # iterating list of numbers for i in self .number: # creating label for each number label = QLabel( str (i), self ) # adding background color and border label.setStyleSheet("border : 1px solid black; background : white;") # aligning the text label.setAlignment(Qt.AlignTop) # setting geometry using local counter # first parameter is distance from left # and second is distance from top # third is width and fourth is height label.setGeometry( 50 + c * 30 , 50 , 20 , i * 10 + 10 ) # adding label to the label list self .label_list.append(label) # incrementing local counter c = c + 1 # creating push button to start the search self .search_button = QPushButton("Start Search", self ) # setting geometry of the button self .search_button.setGeometry( 100 , 270 , 100 , 30 ) # adding action to the search button self .search_button.clicked.connect( self .search_action) # creating push button to pause the search pause_button = QPushButton("Pause", self ) # setting geometry of the button pause_button.setGeometry( 100 , 320 , 100 , 30 ) # adding action to the search button pause_button.clicked.connect( self .pause_action) # creating label to show the result self .result = QLabel("To search : " + str ( self .desired), self ) # setting geometry self .result.setGeometry( 350 , 280 , 200 , 40 ) # setting style sheet self .result.setStyleSheet("border : 3px solid black;") # adding font self .result.setFont(QFont( 'Times' , 10 )) # setting alignment self .result.setAlignment(Qt.AlignCenter) # creating a timer object timer = QTimer( self ) # adding action to timer timer.timeout.connect( self .showTime) # update the timer every 200 millisecond timer.start( 200 ) # method called by timer def showTime( self ): # checking if flag is true if self .start: # linear search # checking if the element is equal to desired element if self .label_list[ self .counter].text() = = str ( self .desired): # make its color green self .label_list[ self .counter].setStyleSheet( "border : 1px solid black; background : lightgreen;") # show result in result label self .result.setText("Found at index : " + str ( self .counter)) # make the start flag false self .start = False # resetting the counter self .counter = 0 # if element is not equal else : # make the label color grey self .label_list[ self .counter].setStyleSheet( "border : 1px solid black; background : grey;") # increment the counter self .counter + = 1 # if counter value become equal to list length if self .counter = = len ( self .label_list): # make start flag false self .start = False # show result i.e not found self .result.setText("Not Found") # method called by search button def search_action( self ): # making flag true self .start = True # showing text in result label self .result.setText("Started searching...") # method called by pause button def pause_action( self ): # making flag false self .start = False # showing text in result label self .result.setText("Paused") # 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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