break和continue语句：

break、continue和C的语法是一样的。break跳出最内层的for/while循环；continue会停止当前枚举，开始下一次枚举。

>>> for n in range(2, 10):
...     for x in range(2, n):
...         if n % x == 0:
...             print n, 'equals', x, '*', n/x
...             break
...     else:
...         # loop fell through without finding a factor
...         print n, 'is a prime number'
... 
2 is a prime number
3 is a prime number
4 equals 2 * 2
5 is a prime number
6 equals 2 * 3
7 is a prime number
8 equals 2 * 4
9 equals 3 * 3

比较有意思的是for/while也可以有else。在循环没有被break中止，而是循环完毕的时候就会执行else语句块。