练习题

with open(‘test4.txt‘,‘w‘,encoding=‘utf-8‘) as f:
    while True:
        inp = input("请输入内容:")
        if inp == ‘q‘:
            break
        f.write(inp + ‘\n‘)
with open(‘test4.txt‘,‘r‘,encoding=‘utf-8‘) as f:
    print(f.read())

with open(‘test3.py‘,encoding=‘utf8‘) as f:
    d = dict()
    for line in f:
        vvv=line.strip(‘\n‘).split(":")[0]
        kkk=line.strip(‘\n‘).split(":")[1]
        if not len(line):
            continue
        d[vvv] = kkk
    while True:
        a = input("用户名：").strip()
        b = input("密码：").strip()
        if a in d.keys() and b == d[a]:
            print("登陆成功")
        else:
            print("用户名或密码错误")

import random
sts = ‘‘
for i in range(5):
    sts += random.choice([str(random.randint(0,9)),chr(random.choice([random.randint(65,90),random.randint(97,122)]))])
print(sts)

lis = [1,2,3,4]
k=[]
for a in lis:
    for b in lis:
        for c in lis:
            d=str(a)+str(b)+str(c)
            if d[0] != d[1] and d[1] != d[2] and d[0] !=d[2]:
                k.append(int(d))
print(len(k))
print(k)

24
[123, 124, 132, 134, 142, 143, 213, 214, 231, 234, 241, 243, 312, 314, 321, 324, 341, 342, 412, 413, 421, 423, 431, 432]