现有两个字典dict如下：

dict1={1:[1,11,111],2:[2,22,222]}

dict2={3:[3,33,333],4:[4,44,444]}

合并两个字典得到类似：

{1:[1,11,111],2:[2,22,222],3:[3,33,333],4:[4,44,444]}

方法1：

dictMerged1=dict(dict1.items()+dict2.items())

方法2：

dictMerged2=dict(dict1, **dict2)

方法2等同于：

dictMerged=dict1.copy()

dictMerged.update(dict2)

或者：

dictMerged=dict(dict1)

dictMerged.update(dict2)

方法2比方法1速度快很多，用timeit测试如下

[root@localhost ~]# python -m timeit -s 'dict1=dict2=dict((i,i) for i in range(100))' 'dictMerged1=dict(dict1.items()+dict2.items())'

100000 loops, best of 3: 16.4 usec per loop

[root@localhost ~]# python -m timeit -s 'dict1=dict2=dict((i,i) for i in range(100))' 'dictMerged2=dict(dict1,**dict2)'

100000 loops, best of 3: 5.84 usec per loop

[root@localhost ~]# python -m timeit -s 'dict1=dict2=dict((i,i) for i in range(100))' 'dictMerged3=dict(dict1)' 'dictMerged3.update(dict2)'

100000 loops, best of 3: 6.07 usec per loop

[root@localhost ~]# python -m timeit -s 'dict1=dict2=dict((i,i) for i in range(100))' 'dictMerged4=dict1.copy()' 'dictMerged4.update(dict2)'

100000 loops, best of 3: 5.84 usec per loop