五、python的练习题

1、输入一行字符，分别统计出其中英文字母、空格、数字和其他字符的个数。

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2018/6/5 17:53
# @Author  : chenjiahe
# @File    : count.py

#用isdigit函数判断是否数字
#用isalpha判断是否字母
#用isalnum判断是否数字和字母的组合
while 1:
    strings = input("Please input a strings(quit will exit): ")
    alpha, dig, space, other  = 0, 0, 0, 0
    if strings.strip() == "quit":
        exit(1)

    for i in strings:
        if i.isalpha():
            alpha += 1
        elif i.isdigit():
            dig += 1
        elif i.isspace():
            space += 1
        else:
            other += 1
    print("alpha:{0}".format(alpha))
    print("dig:{0}".format(dig))
    print("space:{0}".format(space))
    print("other:{0}".format(other))

执行结果

2、99乘法表

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2018/6/5 18:33
# @Author  : chenjiahe
# @File    : 9*9.py

for a in range(1,10):
    for b in range(1,a+1):
        print("{0} x {1} = {2}  ".format(a,b,a*b),end='  ')

    print()

结果：

3、九宫格（数独）

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2018/6/6 16:11
# @Author  : chenjiahe
# @File    : 九宫格.py
'''
九宫格
                      -------------
                      | A | B | C |
                      | D | E | F |
                      | G | H | I |
                      -------------
所有的横竖斜线加起来都等于15
'''

number = [1,2,3,4,5,6,7,8,9]
count = 1
for A in number:
    a = number.copy()
    a.remove(A)
    for B in a:
        b = a.copy()
        b.remove(B)
        for C in b:
            c = b.copy()
            c.remove(C)
            for D in c:
                d = c.copy()
                d.remove(D)
                for E in d:
                    e = d.copy()
                    e.remove(E)
                    for F in e:
                        f = e.copy()
                        f.remove(F)
                        for G in f:
                            g = f.copy()
                            g.remove(G)
                            for H in g:
                                h = g.copy()
                                h.remove(H)
                                for I in h:
                                    if((A+B+C == D+E+F == G+H+I == A+D+G == B+E+H == C+F+I ==A+E+I == C+E+G == 15)):
                                        print('''
                                        方法{9}
                                       -------------------
                                       | {0} | {1} | {2} |
                                       | {3} | {4} | {5} |
                                       | {6} | {7} | {8} |
                                       -------------------
                                        '''.format(A,B,C,D,E,F,G,H,I,count))
                                        count += 1

结果：

4、ABCD乘九=DCBA,A=? B=? C=? D=?

#ABCD乘九=DCBA,A=? B=? C=? D=? 答案: a=1,b=0,c=8,d=9 1089*9=9801

for a in range(1,10):
    for b in range(0,10):
        for c in range(0,10):
            for d in range(1,10):
                if ((a*1000 + b*100 + c*10 +d)*9 == (d*1000 +c*100 +b*10 + a)):
                    print("a = {0}".format(a))
                    print("b = {0}".format(b))
                    print("c = {0}".format(c))
                    print("d = {0}".format(d))
                    print("{0}{1}{2}{3}x9={3}{2}{1}{0}".format(a,b,c,d))

结果：

 5、阶乘

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2018/6/6 18:28
# @Author  : chenjiahe
# @File    : 阶乘.py

'''
计算n个阶乘之和
0! + 1! + 2! …… + n!
n! = n*(n-1)*(n-2)*(n-1）……*1
'''

#计算单个阶乘
def jc(n):
    result = 1
    if n == 0:
        return result
    else:
        for i in range(1,n+1):
            result *= i
        return result

#计算阶乘之和

n = input("计算n的阶乘之和:")
count = 0
for i in range(0,int(n)+1):
    count += jc(i)
print("{0}的阶乘之和是{1}".format(n,count))

结果：

 6、面试题

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time    : 2018/6/7 14:07
# @Author  : chenjiahe
# @File    : 面试题.py

'''
用python完成转换序列的字符，有一串字符串，包含只包含四个字母，GCTA，现在需要进行以下转换:
*'G' ->'C'
*'C' ->'G'
*'T' ->'A'
*'A' ->'U'
如果序列中有不包含这四个字母的字符，就返回空。举例：
1.'ACGTGGTCTTAA' -> 'UGCACCAGAAUU'
2.'ACGTXXXCTTAA' -> ''
'''

while 1:
    string1 = input("Please input a string only with 'G' 'C' 'T' 'A': ")
    string2 = ''
    length1 = len(string1)
    for i in range(0,length1):
        if ((string1[i] == 'G')):
            string2 = string2 + 'C'
        elif ((string1[i] == 'C')):
            string2 = string2 + 'G'
        elif ((string1[i] == 'T')):
            string2 = string2 + 'A'
        elif ((string1[i] == 'A')):
            string2 = string2 + 'U'
        else:
            print(' ')
            exit(1)
    print("{0}".format(string2))

结果：