day 16 - 2 内置函数（二）练习

name=[\'alex\',\'wupeiqi\',\'yuanhao\',\'nezha\']
def func(n):
    return n+\'_sb\'

#ret = map(func,name)   #这里的 ret 是一个迭代器，和可迭代的是不同的
#print(list(ret))       #迭代器 for 循环完了 就没有值了 可迭代的每次 for 循环都会生成一个迭代器

#print(list(map(func,name)))

print(list(map(lambda n:n+\'_sb\',name))) #内置函数

num = [1,3,5,6,7,8]

def func2(i):
    return i % 2 == 0

print(list(filter(func2,num)))
print(list(filter(lambda i:i % 2 == 0,num)))

#lambda 嵌套 三元运算符
num = [1,3,5,6,7,8]
def func(x):
    if x%2 == 0:
        return True

ret = filter(lambda x:True if x%2 == 0 else False,num) #以及列表推导式
print(list(ret))

with open(\'E:/py/log/file.txt\',encoding=\'GBK\')as f:
    l = f.readlines()
pages,mod = divmod(len(l),5)
if mod != 0:
    pages +=1
page_num = int(input(\'请输入页码：\'))
if page_num < 0 or page_num == 0 or page_num > pages:
    print(\'请输入1-\'+str(pages)+\'的页数\')
elif page_num == pages and mod != 0:
    for i in range(mod):
        print(l[(page_num-1)*5+i].strip())
else:
    for i in range(5):
        print(l[(page_num-1)*5+i].strip

portfolio = [
    {\'name\': \'IBM\', \'shares\': 100, \'price\': 91.1},
    {\'name\': \'AAPL\', \'shares\': 50, \'price\': 543.22},
    {\'name\': \'FB\', \'shares\': 200, \'price\': 21.09},
    {\'name\': \'HPQ\', \'shares\': 35, \'price\': 31.75},
    {\'name\': \'YHOO\', \'shares\': 45, \'price\': 16.35},
    {\'name\': \'ACME\', \'shares\': 75, \'price\': 115.65}
]　　

#4.1、计算购买每支股票的总价
ret = map(lambda dic:{dic[\'name\']:round(dic[\'shares\']*dic[\'price\'],2)},portfolio)
print(list(ret))


# 4.2、用filter过滤出，单价大于100的股票有哪些
ret = filter(lambda p:p[\'name\'] if p[\'price\']>100 else False,portfolio)
print(list(ret))

ret = filter(lambda dic:True if dic[\'price\'] > 100 else False,portfolio)
print(list(ret))

ret = filter(lambda dic:dic[\'price\'] > 100,portfolio)
print(list(ret))

d = lambda p:p*2
t = lambda p:p*3
x = 2
x = d(x) #x = 4
x = t(x) #x = 12
x = d(x) #x = 24
print(x)

# max min sorted filter map
# 匿名函数 == 内置函数，因为匿名函数往往与内置函数一起使用

ret = zip(((\'a\'),(\'b\')),((\'c\'),(\'d\')))
res = map(lambda t:{t[0]:t[1]},ret)
print(list(res))

def multipliers():
    return [lambda x:i*x for i in range(4)]
print([m(2) for m in multipliers()])
#结果 [6, 6, 6, 6]

#请修改 multipliers 的定义来产生期望的结果。
def multipliers():
    return (lambda x:i*x for i in range(4))
print([m(2) for m in multipliers()])
#结果 [0, 2, 4, 6]