>>> d = {'a':1, 'b':2} 
>>> d 
{'b': 2, 'a': 1} 
>>> L = [('Jonh',18), ('Nancy',19)] 
>>> d = dict(L) #通过包含键值的列表创建 
>>> d 
{'Jonh': 18, 'Nancy': 19} 
>>> T = tuple(L) 
>>> T 
(('Jonh', 18), ('Nancy', 19)) 
>>> d = dict(T) #通过包含键值的元组创建 
>>> d 
{'Jonh': 18, 'Nancy': 19} 
>>> d = dict(x = 1, y = 3) #通过关键字参数创建 
>>> d 
{'x': 1, 'y': 3} 
>>> d[3] = 'z' 
>>> d 
{3: 'z', 'x': 1, 'y': 3} 

>>> d 
{3: 'z', 'y': 3} 
>>> L1 = [1,2,3] 
>>> d.fromkeys(L1) 
{1: None, 2: None, 3: None} 
>>> {}.fromkeys(L1,'nothing') 
{1: 'nothing', 2: 'nothing', 3: 'nothing'} 
>>> dict.fromkeys(L1,'over') 
{1: 'over', 2: 'over', 3: 'over'} 

>>> d 
{3: 'z', 'x': 1, 'y': 3} 
>>> d[3] 
'z' 
>>> d['x'] 
1 
>>> d[0] 
Traceback (most recent call last): 
 File "<pyshell#26>", line 1, in <module> 
 d[0] 
KeyError: 0 

>>> d = {'x':1,'y':3} 
>>> len(d) 
2 
>>> 'x' in d 
True 
>>> 'z' not in d 
True 

>>> d 
{'x': 1, 'y': 3} 
>>> d['x'] = 1.5 
>>> d 
{'x': 1.5, 'y': 3} 
>>> d['z'] = 5 
>>> d 
{'z': 5, 'x': 1.5, 'y': 3} 

>>> d = {'z': 5, 'x': 1.5, 'y': 3} 
>>> del d['x'] 
>>> d 
{'z': 5, 'y': 3} 
>>> del d['x'] 
Traceback (most recent call last): 
 File "<pyshell#66>", line 1, in <module> 
 del d['x'] 
KeyError: 'x' 

>>> d 
{'z': 5, 'y': 3} 
>>> d.copy() 
{'z': 5, 'y': 3} 

>>> d = {'z': 5, 'x': 1.5, 'y': 3} 
>>> d.get('x') 
1.5 
>>> del d['x'] 
>>> d.get('x') 
>>> d.get('x','nothing') 
'nothing' 

>>> d = {'z': 5, 'x': 1.5, 'y': 3} 
>>> d.items() 
dict_items([('z', 5), ('x', 1.5), ('y', 3)]) 
>>> list(d.items()) 
[('z', 5), ('x', 1.5), ('y', 3)] 

>>> d.keys() 
dict_keys(['z', 'x', 'y']) 
>>> for x in d.keys(): 
 print(x) 
 
  
z 
x 
y 

>>> d = {'z': 5, 'x': 1.5, 'y': 3} 
>>> d.pop('x') 
1.5 
>>> d.pop('x') 
Traceback (most recent call last): 
 File "<pyshell#92>", line 1, in <module> 
 d.pop('x') 
KeyError: 'x' 

>>> d = {'z': 5, 'x': 1.5, 'y': 3} 
>>> d.popitem() 
('z', 5) 
>>> d.popitem() 
('x', 1.5) 

>>> d = {'z': 5, 'x': 1.5, 'y': 3} 
>>> d.setdefault('x') 
1.5 
>>> del d['x'] 
>>> d.setdefault('x','Look!') 
'Look!' 
>>> d 
{'z': 5, 'x': 'Look!', 'y': 3} 

>>> d1 = {'x':1, 'y':3} 
>>> d2 = {'x':2, 'z':1.4} 
>>> d1.update(d2) 
>>> d1 
{'z': 1.4, 'x': 2, 'y': 3} 

>>> d1 
{'z': 1.4, 'x': 2, 'y': 3} 
>>> d1.values() 
dict_values([1.4, 2, 3]) 
>>> list(d1.values()) 
[1.4, 2, 3]