brek和continue
>>> for i in range(10):
... if i==2:continue
... print i
...
0
1
3
4
5
6
7
8
9
>>> for i in range(10):
... if i==2:break
... print i
...
0
1
>>> for i in range(10):
... if i==2:continue
... print i
...
0
1
3
4
5
6
7
8
9
>>> for i in range(10):
... if i==2:break
... print i
...
0
1