55、学习使用按位取反~。
程序分析：~0=1; ~1=0;
(1)先使a右移4位。
(2)设置一个低4位全为1,其余全为0的数。可用~(~0<<4)
(3)将上面二者进行&运算。
#python3.7 if __name__ == '__main__':
a = 234
b = ~a
print('The a\'s 1 complement is %d' % b)
a = ~a
print('The a\'s 2 complement is %d' % a)
56、画图，学用circle画圆形。
#python3.7
from tkinter import * if __name__ == '__main__': canvas = Canvas(width = 800, height = 600, bg = 'purple')
canvas.pack(expand = YES, fill = BOTH)
k = 1
j = 1
for i in range(0, 26):
canvas.create_oval(310 - k, 250 - k, 310 + k, 250 + k, width = 1)
k += 1
j += 0.3 mainloop()
57、画图，学用line画直线。
#python3.7
from tkinter import * if __name__ == '__main__':
canvas = Canvas(width=300, height=300, bg='gold')
canvas.pack(expand=YES, fill=BOTH)
x0 = 263
y0 = 263
x1 = 275
y1 = 275
for i in range(19):
canvas.create_line(x0, y0, x1, y1, width=1, fill='red')
x0 = x0 - 5
y0 = y0 - 5
x1 = x1 + 5
y1 = y1 + 5 x0 = 263
y0 = 263
y1 = 275
for i in range(21):
canvas.create_line(x0, y0, x0, y1, fill='red')
x0 += 5
y0 += 5
y1 += 5 mainloop()
58、画图，学用rectangle画方形。
程序分析：rectangle(int left, int top, int right, int bottom)
参数说明：(left ，top )为矩形的左上坐标，(right,bottom)为矩形的右下坐标，两者可确定一个矩形的大小。
#python3.7
from tkinter import * if __name__ == '__main__':
root = Tk()
root.title('Canvas')
canvas = Canvas(root, width = 400, height = 400, bg = 'yellow')
x0 = 263
y0 = 263
x1 = 275
y1 = 275
for i in range(19):
canvas.create_rectangle(x0, y0, x1, y1)
x0 -= 5
y0 -= 5
x1 += 5
y1 += 5 canvas.pack()
root.mainloop()
59、画图，综合例子。
程序分析：利用for循环控制100-999个数，每个数分解出个位，十位，百位。
#python3.7
from tkinter import *
import math if __name__ == '__main__':
canvas = Canvas(width = 300, height = 300, bg = 'green')
canvas.pack(expand = YES, fill = BOTH)
x0 = 150
y0 = 100
canvas.create_oval(x0 - 10, y0 - 10, x0 + 10, y0 + 10)
canvas.create_oval(x0 - 20, y0 - 20, x0 + 20, y0 + 20)
canvas.create_oval(x0 - 50, y0 - 50, x0 + 50, y0 + 50)
B = 0.809
for i in range(16):
a = 2 * math.pi / 16
x = math.ceil(x0 + 48 * math.cos(a))
y = math.ceil(y0 + 48 * math.sin(a) * B)
canvas.create_line(x0, y0, x, y, fill = 'red')
canvas.create_oval(x0 - 60, y0 - 60, x0 + 60, y0 + 60) for k in range(501):
for i in range(17):
a = (2 * math.pi / 16) * i + (2 * math.pi / 180) * k
x = math.ceil(x0 + 48 * math.cos(a))
y = math.ceil(y0 + 48 + math.sin(a) * B)
canvas.create_line(x0, y0, x, y, fill = 'red')
for j in range(51):
a = (2 * math.pi / 16) * i + (2 * math.pi / 180) * k - 1
x = math.ceil(x0 + 48 * math.cos(a))
y = math.ceil(y0 + 48 * math.sin(a) * B)
canvas.create_line(x0, y0, x, y, fill = 'red')
mainloop()
60、计算字符串长度。
#python3.7 sStr1 = 'strlen'
print(len(sStr1))
参考资料：
1、Python 100例
2、python3图形界面简单案例（tkinter）：https://blog.csdn.net/lyhdream/article/details/17514431