name=input('姓名>>: ')

res='SB' if name == 'alex' else 'NB'

print(res)

l = []

for i in range(10):

    if i >= 5:

        l.append('egg%s' % i)

print(l)

####列表解析

l = ['egg%s' % i for i in range(10) if i >= 5]

print(l)

g = ('egg%s' % i for i in range(1000))   ###用在数据量比较大的场景下

print(g)

print(next(g))

print(next(g))

print(next(g))

##############################################

###把a文件里的内容最长的一行打印出来

with open('a.txt', encoding='utf-8') as f:

    # res=max((len(line) for line in f))  ###[len(line) for line in f]

    res = max(len(line) for line in f)####(len(line) for line in f) ，统计每一行的长度

    print(res)

print(max([1, 2, 3, 4, 5, 6]))###求列表中最大值

#####此方法适用大文件

with open('a.txt', encoding='utf-8') as f:

    g = (len(line) for line in f)

    print(max(g))

res = sum(i for i in range(3))    #sum求和

print(res)

'''
1、求总共花了多少钱
db.txt文件内容：

apple 10 3
tesla 100000 1
mac 3000 2
lenovo 30000 3
chicken 10 3

'''

####笨拙的方法

with open('db.txt', encoding='utf-8') as f:

    l = []

    for line in f:

        goods = line.split()##取出每一行按空格做切分

        price = float(goods[1])###取出商品的价钱

        count = int(goods[2])####取出商品的个数

        cost = price * count####价钱乘以个数

        l.append(cost)#加入到列表中

    print(sum(l))  # 196060.0

####利用生成器表达式

with open('db.txt', encoding='utf-8') as f:

    l = (float(line.split()[1]) * int(line.split()[2]) for line in f)

    print(sum(l))

###把db文件里的商品取出来放到一个列表里去，最终实现[{'name': 'apple', 'price': 333, 'count': 3}, ]

with open('db.txt', encoding='utf-8') as f:

    info = [{'name': line.split()[0],

             'price': float(line.split()[1]),

             'count': int(line.split()[2])} for line in f if float(line.split()[1]) >= 30000]

    print(info)