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 implementationÂ
Python3
# importing librariesfrom PyQt5.QtWidgets import *from PyQt5 import QtCore, QtGuifrom PyQt5.QtGui import *from PyQt5.QtCore import *import sysÂ
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class Window(QMainWindow):Â
    # list of numbers    number = [2, 3, 6, 9, 8, 12, 16, 7, 10, 5, 4, 11, 2, 13]    def __init__(self):        super().__init__()Â
        # setting title        self.setWindowTitle("Linear search ")Â
        # setting geometry        self.setGeometry(100, 100, 600, 400)Â
        # calling method        self.UiComponents()Â
        # showing all the widgets        self.show()Â
    # method for widgets    def UiComponents(self):Â
        # start flag        self.start = FalseÂ
        # list to hold labels        self.label_list = []Â
        # desired value        self.desired = 11Â
        # counter for keeping index        self.counter = 0Â
        # local counter        c = 0Â
        # iterating list of numbers        for i in self.number:Â
            # creating label for each number            label = QLabel(str(i), self)Â
            # adding background color and border            label.setStyleSheet("border : 1px solid black;                                 background : white;")Â
            # aligning the text            label.setAlignment(Qt.AlignTop)Â
            # 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)Â
            # adding label to the label list            self.label_list.append(label)Â
            # incrementing local counter            c = c + 1Â
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        # creating push button to start the search        self.search_button = QPushButton("Start Search", self)Â
        # setting geometry of the button        self.search_button.setGeometry(100, 270, 100, 30)Â
        # adding action to the search button        self.search_button.clicked.connect(self.search_action)Â
        # creating push button to pause the search        pause_button = QPushButton("Pause", self)Â
        # setting geometry of the button        pause_button.setGeometry(100, 320, 100, 30)Â
        # adding action to the search button        pause_button.clicked.connect(self.pause_action)Â
        # creating label to show the result        self.result = QLabel("To search : " + str(self.desired), self)Â
        # setting geometry        self.result.setGeometry(350, 280, 200, 40)Â
        # setting style sheet        self.result.setStyleSheet("border : 3px solid black;")Â
        # adding font        self.result.setFont(QFont('Times', 10))Â
        # setting alignment        self.result.setAlignment(Qt.AlignCenter)Â
        # creating a timer object        timer = QTimer(self)Â
        # adding action to timer        timer.timeout.connect(self.showTime)Â
        # update the timer every 200 millisecond        timer.start(200)Â
    # method called by timer    def showTime(self):Â
        # checking if flag is true        if self.start:            # linear searchÂ
            # checking if the element is equal to desired element            if self.label_list[self.counter].text() == str(self.desired):Â
                # make its color green                self.label_list[self.counter].setStyleSheet(                                  "border : 1px solid black;                                    background : lightgreen;")Â
                # show result in result label                self.result.setText("Found at index : "                                     + str(self.counter))Â
                # make the start flag false                self.start = FalseÂ
                # resetting the counter                self.counter = 0Â
            # if element is not equal            else:Â
                # make the label color grey                self.label_list[self.counter].setStyleSheet(                                  "border : 1px solid black;                                   background : grey;")Â
            # increment the counter            self.counter += 1Â
            # if counter value become equal to list length            if self.counter == len(self.label_list):Â
                # make start flag false                self.start = FalseÂ
                # show result i.e not found                self.result.setText("Not Found")Â
    # method called by search button    def search_action(self):Â
        # making flag true        self.start = TrueÂ
        # showing text in result label        self.result.setText("Started searching...")Â
    # method called by pause button    def pause_action(self):Â
        # making flag false        self.start = FalseÂ
        # showing text in result label        self.result.setText("Paused")Â
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# create pyqt5 appApp = QApplication(sys.argv)Â
# create the instance of our Windowwindow = Window()Â
# start the appsys.exit(App.exec()) |
Output :
