作业day17

2020-06-23

1、文件a.txt内容如下,标题为:姓名,性别,年纪,薪资
egon male 18 3000
alex male 38 30000
wupeiqi female 28 20000
yuanhao female 28 10000

要求:
从文件中取出每一条记录放入列表中,
列表的每个元素都是{'name':'egon','sex':'male','age':18,'salary':3000}的形式

with open('a.txt', 'r', encoding='utf-8') as f:
    l = []
    for line in f:
        dic = {}
        name, sex, age, salary = line.strip('\n').split(" ")
        dic['name'] = name
        dic['sex'] = sex
        dic['age'] = int(age)
        dic['salary'] = int(salary)
        l.append(dic)
print(l)

2、根据1得到的列表,取出薪资最高的人的信息

info1 = max(l ,key = lambda i: i["salary"])
print(info1)

3、根据1得到的列表,取出最年轻的人的信息

info2 = min(l, key = lambda i: i['age'])
print(info2)

4、根据1得到的列表,取出所有人的薪资之和

all_salaries = sum([item['salary'] for item in l])
print(all_salaries)

5、根据1得到的列表,取出所有的男人的名字

name_male = [item['name'] for item in l if item['sex'] == 'male']
print(name_male)

6、根据1得到的列表,将每个人的信息中的名字映射成首字母大写的形式

for item in l:
    item['name'] = item['name'].capitalize()
print(l)

7、根据1得到的列表,过滤掉名字以a开头的人的信息

new_l = [item for item in l if not item['name'].startswith('a')]
print(new_l)

8、将names=['egon','alex_sb','wupeiqi','yuanhao']中的名字全部变大写

names = ['egon', 'alex_sb', 'wupeiqi', 'yuanhao']
new_names = [name.upper() for name in names]
print(new_names)

9、将names=['egon','alex_sb','wupeiqi','yuanhao']中以sb结尾的名字过滤掉，然后保存剩下的名字长度

names = ['egon', 'alex_sb', 'wupeiqi', 'yuanhao']
name_length = [len(name) for name in names if not name.endswith('sb')]
print(name_length)

10、求文件a.txt中最长的行的长度（长度按字符个数算，需要使用max函数）

with open('info.txt', mode='r', encoding='utf-8') as f:
    length = [len(line) for line in f]
res = max(length)
print(res)

11、求文件a.txt中总共包含的字符个数？思考为何在第一次之后的n次sum求和得到的结果为0？（需要使用sum函数）

length = []
with open('a.txt', mode='r', encoding='utf-8') as f:
　　length = [len(line) for line in f]
print(sum(length))

12、思考题

with open('a.txt') as f:
　　g=(len(line) for line in f)
print(sum(g))   #为何报错？

print(sum(g))应该写进文件操作里面,不应该写在顶级

13、文件shopping.txt内容如下

mac,20000,3
lenovo,3000,10
tesla,1000000,10
chicken,200,1
求总共花了多少钱？

打印出所有商品的信息，格式为[{'name':'xxx','price':333,'count':3},...]

l1 = []
with open('shopping.txt') as f:
    for line in f:
        name, price, count = line.strip('\n').split(',')
        dic = {}
        dic['name'] = name
        dic['price'] = int(price)
        dic['count'] = int(count)
        l1.append(dic)
print(l1)
money = sum([item['price'] * item['count'] for item in l1])
print(money)

14、使用递归打印斐波那契数列(前两个数的和得到第三个数，如：0 1 1 2 3 4 7...)

def func(a, b):
    print(a + b, end=' ')
    if b > 10000:
        return
    func(b, a + b)


func(0, 1)

15、一个嵌套很多层的列表，如l=［1,2,[3,[4,5,6,[7,8,[9,10,[11,12,13,[14,15]]]]]]］，用递归取出所有的值

l = [1, 2, [3, [4, 5, 6, [7, 8, [9, 10, [11, 12, 13, [14, 15]]]]]]]
def func1(l):
    for i in l:
        if type(i) is list:
            func1(i)
        else:
            print(i)
func1(l)