Python 100 实例之（81 - 90）

example_081.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 求未知数 '

__author__ = 'Kevin Gong'

a = 809
for i in range(10, 100):
    b = i * a
    if b >= 1000 and b <= 10000 and 8 * i < 100 and 9 * i >= 100:
        print(b, '= 800 * ', i, ' + 9 * ',i)

for i in range(10, 100):
    if 8 * i > 99 or 9 * i < 100:
        continue
    if 809 * i == 800 * i + 9 * i:
        print(i)
        break

example_082.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 八进制转换为十进制 '

__author__ = 'Kevin Gong'

n = eval('0o' + str(int(input('输入一个八进制的数：'))))
print(n)

example_083.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 求 0—7 所能组成的奇数个数 '

__author__ = 'Kevin Gong'

if __name__ == '__main__':
    sum = 4
    s = 4
    for i in range(2, 9):
        print(sum)
        if i <= 2:
            s *= 7
        else:
            s *= 8
        sum += s
    print('sum = %d' % sum)

example_084.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 连接字符串 '

__author__ = 'Kevin Gong'

delimiter = ','
mylist = ['Brazil', 'Russia', 'India', 'China']
print(delimiter.join(mylist))

example_085.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 输入一个奇数，然后判断最少几个 9 除于该数的结果为整数。 '

__author__ = 'Kevin Gong'

if __name__ == '__main__':
    n = int(input('请输入一个奇数：'))
    i = 1
    c9 = 1
    m9 = 9
    sum = 9
    while i != 0:
        if sum % n == 0:
            i = 0
        else:
            m9 *= 10
            sum += m9
            c9 += 1
    print('%d 个 9 可以被 %d 整除：%d' % (c9, n, sum))
    r = sum / n
    print('%d / %d = %d' % (sum, n, r))

example_086.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 两个字符串连接程序 '

__author__ = 'Kevin Gong'

a = 'guangtou'
b = 'feipang'
print(b + a)

example_087.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 结构体变量传递 '

__author__ = 'Kevin Gong'

if __name__ == '__main__':
    class student:
        x = 0
        c = 0
    def f(stu):
        stu.x = 20
        stu.c = 'c'
    a = student()
    a.x = 3
    a.c = 'a'
    f(a)
    print(a.x, a.c)

example_088.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 读取7个数（1—50）的整数值，每读取一个值，程序打印出该值个数的＊。 '

__author__ = 'Kevin Gong'

if __name__ == '__main__':
    n = 1
    while n <= 7:
        a = int(input('input a number:\n'))
        while a < 1 or a > 50:
            a = int(input('input a number:\n'))
        print(a * '*')
        n += 1

example_089.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 采用公用电话传递数据 '

__author__ = 'Kevin Gong'

from sys import stdout

if __name__ == '__main__':
    a = int(input('输入四个数字：\n'))
    raw = []
    raw.append(a % 10)
    raw.append(a % 100 / 10)
    raw.append(a % 1000 / 100)
    raw.append(a / 1000)

    for i in range(4):
        raw[i] += 5
        raw[i] %= 10
    for i in range(2):
        raw[i],raw[3 - i] = raw[3 -i],raw[i]
    for i in range(3, -1, -1):
        stdout.write(str(raw[i]))

example_090.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

' 列表的使用 '

__author__ = 'Kevin Gong'

testList = [10086, '中国移动', [1, 2, 4, 5]]

# 访问列表长度
print(len(testList))
# 到列表结尾
print(testList[1:])
# 向列表添加元素
testList.append('i\'m new here!')
print (len(testList))
print (testList[-1])
# 弹出列表的最后一个元素  
print (testList.pop(1))
print (len(testList))
print (testList)

matrix = [[1, 2, 3],  
          [4, 5, 6],  
          [7, 8, 9]]  
print (matrix)
print (matrix[1])
col2 = [row[1] for row in matrix]     # get a  column from a matrix  
print (col2)
col2even = [row[1] for row in matrix if  row[1] % 2 == 0]     # filter odd item  
print (col2even)