day 15

内置函数练习

编写 sql 查询语句功能

文件内容：

1,Eva,22,13651054608,IT
2,Vera,23,13304320533,Tearcher
3,Renault,25,1333235322,IT

实现：
装饰器登录
select name, age where age>22
select * where age>22
select * where phone like 133
select * where occ=IT（字符串比较未实现，与年龄的数字比较有冲突 待解决）

#读文件
def dir():
    with open('d:/py/info.txt',encoding='utf-8')as f:
        for line in f:
            line = line.strip().split(',')
            yield line

d =dir()

#实现显示
def view(option,lis):
    dic = {'id':lis[0],'name':lis[1],'age':lis[2],'phone':lis[3],'occ':lis[4]}
    option = option.split().pop(1).split(',')
    for i in option:
        if i in dic:
            print(dic[i],end=' ')
        elif i == '*':
            print(lis)
        else:
            print('输入字段有误')

# sel 判断
def judge(option,condition):
    if '>' in condition:
        a,b = condition.split('>')
        for lis in dir():
            if int(d.__next__()[2]) > int(b):
                view(option,lis)
    elif '<' in condition:
        a,b = condition.split('<')
        for lis in dir():
            if int(d.__next__()[2]) < int(b):
                view(option,lis)
    elif '=' in condition:
        a,b = condition.split('=')
        for lis in dir():
            if int(d.__next__()[2]) == int(b):
                view(option,lis)

#实现 like 查找功能
def like(s):
    if 'like' in s and '*' in s:
        val,con = s.split('like')
        val = val.split().pop().strip()
        con = con.strip()
        for lis in dir():
            if con in d.__next__()[3]:
                print(lis)

#实现登录
def login(f):
    def inner():
        use = input('账号 >>>')
        pwd = input('密码 >>>')
        if use == 'ysg' and pwd == '123':
            ret = f()
            return ret
        else:
            print('登录失败')
    return inner


#实现 select（主函数）
@login
def sel():
        s = input('输入语句 >>>')
        #s = 'select name,age where age>22'
        option,condition = s.split('where')
        condition = condition.strip()
        #strs(s) #实现字符串比较的功能
        like(s)     #实现 like 查找功能
        judge(option,condition)     #实现数字比较的功能
    
sel() 

面试题：阅读代码，说出输出结果

def extendList(val,list=[]):
    list.append(val)
    return list
list = extendList(10)
list2 = extendList(123,[])
list3 = extendList('a')

print("list = %s"%list)
print("list2 = %s"%list2)
print("list3 = %s"%list3)

#结果
list = [10, 'a']
list2 = [123]
list3 = [10, 'a']