Python学习100例之51-60

此Python版本为2.7，其他例子如下：
Python学习100例之1-10
Python学习100例之11-20
Python学习100例之21-30
Python学习100例之31-40
Python学习100例之41-50
Python学习100例之61-70
Python学习100例之71-80
Python学习100例之81-90
Python学习100例之91-100

51.学习使用按位与 &

a = 6   0000 0110
b = 18   0001 0010
print(a & b, '\n')   输出2 0000 0010

52.学习使用按位或 | 。

print(a | b, '\n')   输出22 0001 0110

53.学习使用按位异或 ^

print(a ^ b, '\n')   输出22 0001 0100

54.取一个整数a从右端开始的4〜7位

number = int(input("输入一个整数:")) >> 4
refer = ~(~0 << 4)   第4位为1,其余为0,即为15 0000 1111
print(number & refer, '\n')

55.学习使用按位取反~

print(~a, '\n')

56.画图，学用circle画圆形

import tkinter
from tkinter import *

canvas = Canvas(width=600, height=600, bg='yellow')

canvas.pack(expand=tkinter.constants.YES, fill=tkinter.constants.BOTH)
 expand置1 使能fill属性
 expand置0 关闭fill属性
 fill=X    当GUI窗体大小发生变化时，widget在X方向跟随GUI窗体变化
 fill=Y    当GUI窗体大小发生变化时，widget在Y方向跟随GUI窗体变化
 fill=BOTH 当GUI窗体大小发生变化时，widget在X、Y两方向跟随GUI窗体变化
k = 1
j = 1
for _ in range(0, 20):
    canvas.create_oval(310 - k, 310 - k, 310 + k, 310 + k, width=1)
    k += 10

mainloop()

57.画图，学用line画直线。

import tkinter
from tkinter import *

canvas = Canvas(width=600, height=600, bg='green')
canvas.pack(expand=tkinter.constants.YES, fill=tkinter.constants.BOTH)

x0 = 263
y0 = 263
y1 = 275
x1 = 275
for i in range(19):
    canvas.create_line(x0, y0, x0, y1, width=1, fill='red')
    x0 = x0 - 5
    y0 = y0 - 5
    x1 = x1 + 5
    y1 = y1 + 5

x0 = 263
y1 = 275
y0 = 263
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

import tkinter
from tkinter import *

canvas = Canvas(width=600, height=600, bg='red')
canvas.pack(expand=tkinter.constants.YES, fill=tkinter.constants.BOTH)
x0 = 240
y0 = 240
x1 = 270
y1 = 270
for _ in range(21):
    canvas.create_rectangle(x0, y0, x1, y1, width=2)
    x0 -= 10
    y0 -= 10
    x1 += 10
    y1 += 10
mainloop()

59.画图，综合例子

import tkinter
from tkinter import *


canvas = Canvas(width=400, height=400, bg='orange')
canvas.pack(expand=tkinter.constants.YES, fill=tkinter.constants.BOTH)

x0 = 200
y0 = 200
k = 80
canvas.create_line(x0 - 2 * k, y0 - 2 * k, x0 + 2 * k, y0 + 2 * k)
canvas.create_line(x0 + 2 * k, y0 - 2 * k, x0 - 2 * k, y0 + 2 * k)
for _ in range(2):
    canvas.create_oval(x0 - k, y0 - k, x0 + k, y0 + k)
    canvas.create_rectangle(x0 - k, y0 - k, x0 + k, y0 + k)
    k += 80

mainloop()

60.计算字符串长度

s = input("请输入一个字符串:")
print("字符串的长度为%d" % len(s))