PyQt5 - 二分搜索可视化工具
在本文中，我们将看到如何制作一个 PyQt5 应用程序，它可以可视化二进制搜索算法。
二分搜索：通过重复将搜索间隔分成两半来搜索已排序的数组。从覆盖整个数组的间隔开始。如果搜索键的值小于区间中间的项，则将区间缩小到下半部分。否则将其缩小到上半部分。反复检查，直到找到值或区间为空。 
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 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
Algorithm implementation steps :
1. Create label list corresponding to the given numbers
2. Create variable for the first last and mid 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 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 binary search algorithm
6. Calculate mid value and check if mid value is equal then stop the search and make label green.
7. Show result as found else change the value of first and last search according to the mid value. Make the label grey color and continue the search.
8. If the index of first become greater then index of last stop the search and show result as not found.
下面是实现——
# 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 = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]
def __init__(self):
super().__init__()
# setting title
self.setWindowTitle("Binary 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 = 9
# binary search variable
self.first = 0
self.last = len(self.number) - 1
self.mid = 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 forth 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 300 millisecond
timer.start(300)
# method called by timer
def showTime(self):
# checking if flag is true
if self.start:
# implementing binary search
# finding mid index
self.mid = (self.first + self.last)//2
# if first index become greater than last index
if self.first > self.last:
# make start flag false
self.start = False
# show output as not found
self.result.setText("Not Found")
# if mid value is equal to the desired value
if self.number[self.mid] == self.desired:
# make flag false
self.start = False
# show output in result label
self.result.setText("Found at index : " + str(self.mid))
# set color of label to green
self.label_list[self.mid].setStyleSheet(
"border : 2px solid green; "
"background-color : lightgreen")
# if not equal to mid value
else:
# make color grey
self.label_list[self.mid].setStyleSheet(
"border : 1px solid black; "
"background-color : grey")
# mid value is higher
if self.number[self.mid] > self.desired:
# change last index
self.last = self.mid - 1
# if mid value is smaller
if self.number[self.mid] < self.desired:
# change first index
self.first = self.mid + 1
# 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())
输出 ：