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 ~~~