函数 装饰器 内置函数

一.命名空间和作用域

 二.装饰器

1.无参数

2.函数有参数

3.函数动态参数

 4.装饰器参数 

 三.内置函数

salaries={
    'egon':3000,
    'alex':100000000,
    'wupeiqi':10000,
    'yuanhao':250
}
print(sorted(salaries)) #默认是按照字典salaries的key去排序的
  
print(sorted(salaries,key=lambda x:salaries[x]))

#max
 
salaries={
    'egon':3000,
    'alex':100000000,
    'wupeiqi':10000,
    'yuanhao':250
}
 
print(max(salaries,key=lambda k:salaries[k]))
------------输出结果-------
alex

#enumerate
 
for i in enumerate(['a','b','c','d']):
    print(i)
------------输出结果-------
(0, 'a')
(1, 'b')
(2, 'c')
(3, 'd')

#用filter来处理,得到股票价格大于20的股票名字
shares={
    'IBM':36.6,
    'Lenovo':23.2,
    'oldboy':21.2,
    'ocean':10.2,
}
 
shares = list(filter(lambda x:shares[x] >20,shares))
 
 
#filter
 
#如下，每个小字典的name对应股票名字，shares对应多少股，price对应股票的价格
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}
]
 
#用filter过滤出，单价大于100的股票有哪些
 
name = list(filter(lambda x:x["price"] > 100,portfolio))
print(name)

s=[1,"h",2,"e",[1,2,3],"l",(4,5),"l",{1:"111"},"o"]

from functools import reduce
print(reduce(lambda x,y:x+y,[s[i] for i in range(len(s)) if i % 2 == 1]))
------------------输出结果----
hello

 

#map
 
#用map来处理字符串列表啊,把列表中所有人都变成sb,比方alex_sb
name=['alex','wupeiqi','yuanhao']
 
name_new = list(map(lambda i: i + '_sb', name))
 
 
#用map来处理下述l，然后用list得到一个新的列表，列表中每个人的名字都是sb结尾
l=[{'name':'alex'},{'name':'y'}]
 
l = list(map(lambda x:x["name"] + "sb",l))

#生成列表套字典

type_choices = [
    (1, "Python"),
    (2, "Django"),
    (3, "Flask"),
    (100, "Python全栈"),
    (101, "Linux云计算"),
    (1000, "在线直播"),
    (10000, "免费视频"),
]

map(lambda item: {'nid': item[0], 'title': item[1]}, models.Article.type_choices)

[{'nid': 1, 'title': 'Python'}, {'nid': 2, 'title': 'Django'}]

l1=[1,2,3,4]
s='hel'
obj = list(zip(l1,s))
------------输出结果-------
[(1, 'h'), (2, 'e'), (3, 'l')]
 
 
 
salaries={
    'egon':3000,
    'alex':100000000,
    'wupeiqi':10000,
    'yuanhao':250
}
 
z=list(zip(salaries.values(),salaries.keys()))
------------输出结果-------
[(3000, 'egon'), (100000000, 'alex'), (250, 'yuanhao'), (10000, 'wupeiqi')]




xx = ['id', 'name', 'age', 'phone', 'job']
title = ['1', 'alex', '22', '13651043850', 'IT']

print(list(zip(xx,title)))
print(dict(zip(xx,title)))            按字典的格式输出
------------输出结果-------
[('id', '1'), ('name', 'alex'), ('age', '22'), ('phone', '13651043850'), ('job', 'IT')]
{'id': '1', 'name': 'alex', 'age': '22', 'phone': '13651043850', 'job': 'IT'}