排序算法可视化：如何从紧密的循环内部拉取值以对画布进行动画处理

排序算法可视化：如何从紧密的循环内部拉取值以对画布进行动画处理

利用生成器函数（关键字

yield

），您可以暂停代码中间循环的执行，以花时间显示已更改的画布元素，更新计算等，然后在

next

反复调用生成器时恢复执行，直到排序完成。

我在代码中添加了一些注释，但是最好的方法可能是凝视它，直到您确信自己可以按预期工作为止。这是您需要了解的一种模式，因为它对构造您想要构建的动画非常有用。

import tkinter as tkimport randomdef swap_two_pos(pos_0, pos_1):    Bar1x1, _, Bar1x2, _ = canvas.coords(pos_0)    Bar2x1, _, Bar2x2, _ = canvas.coords(pos_1)    canvas.move(pos_0, Bar2x1-Bar1x1, 0)    canvas.move(pos_1, Bar1x2-Bar2x2, 0)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_two_pos(barList[pos],barList[pos-1])   # <-- updates the display yield      # <-- suspends the execution pos -= 1   # <-- execution resumes here when next is called        lengthList[pos] = cursor        barList[pos] = cursorBar        swap_two_pos(barList[pos],cursorBar)worker = None    # <-- Not a thread in spite of the name.def insertion_sort():     # <-- commands the start of both the animation, and the sort    global worker    worker = _insertion_sort()    animate()def animate():      # <-- commands resuming the sort once the display has been updated         # controls the pace of the animation    global worker    if worker is not None:        try: next(worker) window.after(10, animate)    # <-- repeats until the sort is complete,        except StopIteration: # when the generator is exhausted worker = None        finally: window.after_cancel(animate) # <-- stop the callbacksdef shuffle():    global barList    global lengthList    canvas.delete('all')    xstart = 5    xend = 15    barList = []    lengthList = []    for x in range(1, 60):        randomY = random.randint(1, 390)        x = canvas.create_rectangle(xstart, randomY, xend, 395, fill='red')        barList.append(x)        xstart += 10        xend += 10    for bar in barList:        x = canvas.coords(bar)        length = x[3] - x[1]        lengthList.append(length)    for i in range(len(lengthList)-1):        if lengthList[i] == min(lengthList): canvas.itemconfig(barList[i], fill='blue')        elif lengthList[i] == max(lengthList): canvas.itemconfig(barList[i], fill='green')window = tk.Tk()window.title('Sorting')window.geometry('600x435')canvas = tk.Canvas(window, width='600', height='400')canvas.grid(column=0,row=0, columnspan = 50)insert = tk.Button(window, text='Insertion Sort', command=insertion_sort)shuf = tk.Button(window, text='Shuffle', command=shuffle)insert.grid(column=1,row=1)shuf.grid(column=0, row=1)shuffle()window.mainloop()