Python的dict字典结构操作方法学习笔记

> dict1={} 
> dict2=dict() 
> dict1,dict2 
({}, {}) 

> dict1={1:'a',2:'b',3:'c'} 
> dict1 
{1: 'a', 2: 'b', 3: 'c'} 

> dict1=dict([(1,'a'),(2,'b'),(3,'c')]) 
> dict1 
{1: 'a', 2: 'b', 3: 'c'} 

> dict1={1:'a',2:'b',3:'c'} 
> dict1.get(1) 
'a' 

> type(dict1.get(4)) 
<type 'NoneType'> 

> dict1.get(4,'not found') 
'not found' 

> dict1.keys() 
[1, 2, 3] 

> dict1.values() 
['a', 'b', 'c'] 

> dict1.items() 
[(1, 'a'), (2, 'b'), (3, 'c')] 

> for key in dict1.iterkeys(): 
 print key 
1 
2 
3 

> dict1[4]='d' 
> dict1 
{1: 'a', 2: 'b', 3: 'c', 4: 'd'} 

> dict1[4]='e' 
> dict1 
{1: 'a', 2: 'b', 3: 'c', 4: 'e'} 

> dict1 
{1: 'a', 2: 'b', 3: 'c', 4: 'e'} 
> dict1.setdefault(5,'f') 
'f' 
> dict1.setdefault(5,'g') 
'f' 
> dict1 
{1: 'a', 2: 'b', 3: 'c', 4: 'e', 5: 'f'} 

> def pop_key(d,key): 
 try: 
 d.pop(key) 
 print "sucess" 
 except: 
 print "key is not in dict" 
> dict1 
{1: 'a', 2: 'b'} 
> pop_key(dict1,3) 
key is not in dict 

> def sub_dict2(d,key): 
 if d.has_key(key): 
 d.pop(key) 
 print "sucess" 
 else:print "key is not in dict" 
 
> pop_key(dict1,3) 
key is not in dict 

> list1=[1,2,3] 
> list2=['a','b','c'] 
> dict1=dict(zip(list1,list2)) 
> dict1 
{1: 'a', 2: 'b', 3: 'c'} 

> dict1 
{1: 'a', 2: 'b', 3: 'c'} 
> dict1=dict([(1,'a'),(2,'b'),(3,'c')]) 
> dict1 
{1: 'a', 2: 'b', 3: 'c'} 
> subkeys=[1,3] 
> def sub_dict(d,subkeys): 
 return dict([(k,d.get(k)) for k in subkeys if k in d]) 
 
> print sub_dict(dict1,subkeys) 
{1: 'a', 3: 'c'} 

> def invert_dict(d): 
 return dict([(k,v) for v,k in d.iteritems()]) 
 
> print invert_dict(dict1) 
{'a': 1, 'c': 3, 'b': 2} 
> 

> d2={1:[1],2:[2],3:[3]} 
> d3=d2.copy() 
> d3[1].append(4) 
> d2[1] 
[1, 4] 

> d2={1:[1],2:[2],3:[3]} 
> import copy 
> d3=copy.deepcopy(d2) 
> d3[1].append(4) 
> print d2[1] , d3[1] 
[1] [1, 4] 

> dict1={1: 'a', 2: 'b', 3: 'c'} 
> dict2={1:'x',4:'y'} 
> dict1.update(dict2) 
> dict1 
{1: 'x', 2: 'b', 3: 'c', 4: 'y'} 
> 

> d 
{'a': 'aa', 'c': 'cc', 'b': 'bb'} 
> for i in d: 
 print i,d[i] 
 
a aa 
c cc 
b bb 

> for i,v in d.items(): 
 print i,v 
 
a aa 
c cc 
b bb 

> for (i,v) in d.items(): 
 print i,v 
 
a aa 
c cc 
b bb 

> for k,v in d.iteritems(): 
 print k,v 
 
a aa 
c cc 
b bb 

> d={'hello':[1,4,9],"good":[1,3,6]} 
> d 
{'good': [1, 3, 6], 'hello': [1, 4, 9]} 
> d.setdefault('good',[]).append(7) 
> d 
{'good': [1, 3, 6, 7], 'hello': [1, 4, 9]} 
> d.setdefault('bad',[]).append(2) 
> d 
{'bad': [2], 'good': [1, 3, 6, 7], 'hello': [1, 4, 9]} 
> 

> def addFunc(d,word,pag): 
 d.setdefault(word,set()).add(pag) 
> d={'hello':set([1,4,9]),"good":set([1,3,6])} 
> addFunc(d,'hello',8) 
> d 
{'good': set([1, 3, 6]), 'hello': set([8, 1, 4, 9])} 
> addFunc(d,'bad',8) 
> d 
{'bad': set([8]), 'good': set([1, 3, 6]), 'hello': set([8, 1, 4, 9])} 

> class cat(object): 
 def __init__(self): 
 print 'cat init' 
> class dog(object): 
 def __init__(self): 
 print 'dag init' 
> d={'cat':cat,'dog':dog} 
> def factoryFunc(d,name): 
 if name in d: 
 return d[name]() 
 else: 
 raise Exception("error") 
> cat=factoryFunc(d,'cat') 
cat init 

> def deal_cat(): 
 print 'cat run!!' 
 
> def deal_dog(): 
 print 'dag run!!' 
 
> d={'cat':deal_cat ,'dog':deal_dog } 
> animal='cat' 
> d[animal]() 
cat run!!