*what is use of yield in following code *
these part of following program. I have some knowledge about generator function and yield, but don't have about how it works in for loop.
for i in range(len(lengthList) - 1):
for j in range(len(lengthList) - i - 1):
if(lengthList[j] > lengthList[j + 1]):
lengthList[j] , lengthList[j + 1] = lengthList[j + 1] , lengthList[j]
barList[j], barList[j + 1] = barList[j + 1] , barList[j]
swap(barList[j + 1] , barList[j])
yield
here is complete code
this is for shorting algorithm visualization
import tkinter as tk
import random
Function to swap two bars that will be animated
def swap(pos_0, pos_1):
bar11, _, bar12, _ = canvas.coords(pos_0)
bar21, _, bar22, _ = canvas.coords(pos_1)
canvas.move(pos_0, bar21-bar11, 0)
canvas.move(pos_1, bar12-bar22, 0)
worker = None
#Insertion Sort
def _insertion_sort():
global barList
global lengthList
for i in range(len(lengthList)):
cursor = lengthList[i]
cursorBar = barList[i]
pos = i
while pos > 0 and lengthList[pos - 1] > cursor:
lengthList[pos] = lengthList[pos - 1]
barList[pos], barList[pos - 1] = barList[pos - 1], barList[pos]
swap(barList[pos],barList[pos-1])
yield
pos -= 1
lengthList[pos] = cursor
barList[pos] = cursorBar
swap(barList[pos],cursorBar)
Bubble Sort
def _bubble_sort():
global barList
global lengthList
for i in range(len(lengthList) - 1):
for j in range(len(lengthList) - i - 1):
if(lengthList[j] > lengthList[j + 1]):
lengthList[j] , lengthList[j + 1] = lengthList[j + 1] , lengthList[j]
barList[j], barList[j + 1] = barList[j + 1] , barList[j]
swap(barList[j + 1] , barList[j])
yield
Selection Sort
def _selection_sort():
global barList
global lengthList
for i in range(len(lengthList)):
min = i
for j in range(i + 1 ,len(lengthList)):
if(lengthList[j] < lengthList[min]):
min = j
lengthList[min], lengthList[i] = lengthList[i] ,lengthList[min]
barList[min] , barList[i] = barList[i] , barList[min]
swap(barList[min] , barList[i])
yield
Triggering Fuctions
def insertion_sort():
global worker
worker = _insertion_sort()
animate()
def selection_sort():
global worker
worker = _selection_sort()
animate()
def bubble_sort():
global worker
worker = _bubble_sort()
animate()
Animation Function
def animate():
global worker
if worker is not None:
try:
next(worker)
window.after(10, animate)
except StopIteration:
worker = None
finally:
window.after_cancel(animate)
Generator function for generating data
def generate():
global barList
global lengthList
canvas.delete('all')
barstart = 5
barend = 15
barList = []
lengthList = []
#Creating a rectangle
for bar in range(1, 60):
randomY = random.randint(1, 360)
bar = canvas.create_rectangle(barstart, randomY, barend, 365, fill='yellow')
barList.append(bar)
barstart += 10
barend += 10
#Getting length of the bar and appending into length list
for bar in barList:
bar = canvas.coords(bar)
length = bar[3] - bar[1]
lengthList.append(length)
#Maximum is colored Red
#Minimum is colored Black
for i in range(len(lengthList)-1):
if lengthList[i] == min(lengthList):
canvas.itemconfig(barList[i], fill='red')
elif lengthList[i] == max(lengthList):
canvas.itemconfig(barList[i], fill='black')
Making a window using the Tk widget
window = tk.Tk()
window.title('Sorting Visualizer')
window.geometry('600x450')
#Making a Canvas within the window to display contents
canvas = tk.Canvas(window, width='600', height='400')
canvas.grid(column=0,row=0, columnspan = 50)
#Buttons
insert = tk.Button(window, text='Insertion Sort', command=insertion_sort)
select = tk.Button(window, text='Selection Sort', command=selection_sort)
bubble = tk.Button(window, text='Bubble Sort', command=bubble_sort)
shuf = tk.Button(window, text='Shuffle', command=generate)
insert.grid(column=1,row=1)
select.grid(column=2,row=1)
bubble.grid(column=3,row=1)
shuf.grid(column=0, row=1)
generate()
window.mainloop()
