break 语句和 C 中的类似，用于跳出最近的一级 for 或 while 循环。
循环可以有一个 else 子句；它在循环迭代完整个列表（对于 for ）或执行条件为 false （对于while ）时执行，但循环被 break 中止的情况下不会执行。以下搜索素数的示例程序演示了这个子句:
>>> 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
(Yes, 这是正确的代码。看仔细：else 语句是属于 for 循环之中， 不是 if 语句。)
continue 语句是从 C 中借鉴来的，它表示循环继续执行下一次迭代:
>>> for num in range(2, 10):
... if num % 2 == 0:
... print("Found an even number", num)
... continue
... print("Found a number", num)
Found an even number 2
Found a number 3
Found an even number 4
Found a number 5
Found an even number 6
Found a number 7
Found an even number 8
Found a number 9