review

字典 dict.items()

[root@kube python]# cat demo.py 
#coding:utf-8

drinks = { 
    'martini': {'vodka', 'vermouth'}, 
    'black russian': {'vodka', 'kahlua'}, 
    'white russian': {'cream', 'kahlua', 'vodka'}, 
    'manhattan': {'rye', 'vermouth', 'bitters'}, 
    'screwdriver': {'orange juice', 'vodka'} 
    }
print(drinks.items())
#drinks.items() 获取所有键值对 ，name  为key ,contexts 为 values

for name, contexts in drinks.items():
    if 'vodka' in contexts:
        print(name)
[root@kube python]# 

 list  tuple ,dict  的变化

[root@kube review]# cat demo1.py 
marxes = ['Groucho', 'Chico', 'Harpo']
pythons = ['Chapman', 'Cleese', 'Gilliam', 'Jones', 'Palin']
stooges = ['Moe', 'Curly', 'Larry']


lt = [marxes, pythons,stooges]
print(lt)

tu = marxes,pythons,stooges
print(tu)

dt = {'marxes':marxes, 'pythons':pythons,'stooges':stooges}
print(dt)
[root@kube review]# py demo1.py 
[['Groucho', 'Chico', 'Harpo'], ['Chapman', 'Cleese', 'Gilliam', 'Jones', 'Palin'], ['Moe', 'Curly', 'Larry']]
(['Groucho', 'Chico', 'Harpo'], ['Chapman', 'Cleese', 'Gilliam', 'Jones', 'Palin'], ['Moe', 'Curly', 'Larry'])
{'marxes': ['Groucho', 'Chico', 'Harpo'], 'pythons': ['Chapman', 'Cleese', 'Gilliam', 'Jones', 'Palin'], 'stooges': ['Moe', 'Curly', 'Larry']}
[root@kube review]# 

字典推导式

除了列表，字典也有自己的推导式。最简单的例子就像：

{ key_expression : value_expression for expression in iterable }

 

[root@kube python]# cat demo1.py 
# 1
word = 'letters'
letter_counts = {letter: word.count(letter) for letter in word}
print(letter_counts)


#2
for letter in word:
    print(letter,':',word.count(letter))



[root@kube python]# py demo1.py    #使用字典推导式和for 循环的区别就是，字典活去除相同键值的key:value 值
{'l': 1, 'e': 2, 't': 2, 'r': 1, 's': 1}
l : 1          
e : 2
t : 2
t : 2
e : 2
r : 1
s : 1
[root@kube python]# 

 函数

[root@kube review]# cat demo4.py 
#coding:utf-8

def commentary(color):
    if color == 'red':
        return 'It`s a tomato'
    elif color == 'green':
        return 'this a green pepper'
    else:
        return 'it`s no heaed'

comm1 = commentary('red')
comm2 = commentary('green')
comm3 = commentary('black')
print(comm1)
print(comm2)
print(comm3)
[root@kube review]# py demo4.py 
It`s a tomato
this a green pepper
it`s no heaed
[root@kube review]# 

函数之内部函数

[root@localhost python]# cat demo1.py 
#coding:utf-8

#内部函数的作用是给外部的函数增加字符串 参数：
#相当于将参数传递给 inner 函数并且返

def outer(a,b):
    def inner(aa,bb):
        return aa * bb
    return inner(a,b) 

print(outer(33,44))
[root@localhost python]# py demo1.py 
1452
[root@localhost python]# 

函数之闭包

[root@localhost python]# cat demo2.py 
#coding:utf-8
#内部函数可以看作一个闭包。闭包是一个可以由另一个函数动态生成的函数，并且可以改 变和存储函数外创建的变量的值。
# inner() 函数是一个闭包，存储了 test(saying)  函数的值。

def test1(saying):
    def inner():
        return 'we are inner function ： %s ' % saying
    return inner   #返回的是一个函数

a = test1('hello word')
print(a())

[root@localhost python]# py demo2.py 
we are inner function ： hello word 
[root@localhost python]# 

装饰器

[root@localhost python]# cat demo5.py 
#coding:utf-8

def document_it(func):                                
    def new_function(*args, **kwargs):
        print('Running function:', func.__name__)
        print('Positional arguments:', args)        
        print('Keyword arguments:', kwargs)           
        result = func(*args, **kwargs)        
        print('Result:', result)       
        return result
    return new_function

@document_it                    #将add_ints 作为参数传递给 document_it 装饰器，这意味着  add_ints() 被替换成了 new_function() 函数，如果要执行 add_ints() 的值就需要
def add_ints(a,b):              #在 new_function() 函数中执行 fun(*args,**kwargs)，修饰器就将被修饰的函数作为参数传递给修饰器 
    return a + b
add_ints(3,5)
[root@localhost python]# py demo5.py
Running function: add_ints
Positional arguments: (3, 5)
Keyword arguments: {}
Result: 8
[root@localhost python]#