举例详解Python中循环语句的嵌套使用

Python编程语言允许在一个循环内嵌套另一个循环。下面将介绍几个例子来说明这一概念。

语法

在Python中嵌套循环语句的语法如下：

for iterating_var in sequence:

for iterating_var in sequence:

statements(s)

statements(s)

Python编程语言允许在一个循环内嵌套另一个循环。下面将介绍几个例子来说明这一概念。

语法

在Python中嵌套循环语句的语法如下：

for iterating_var in sequence:

for iterating_var in sequence:

statements(s)

statements(s)

Python编程语言的一个嵌套while循环语句的语法，如下所示：

while expression:

while expression:

statement(s)

statement(s)

在循环嵌套最后需要说明的是，可以把任何类型的循环的任何其他类型的循环里面。例如，for循环内可以放置while循环，反之亦然。

例子

下面的程序使用一个嵌套的循环，从2到100中找出所有的素数：

#!/usr/bin/python

i = 2

while(i < 100):

j = 2

while(j <= (i/j)):

if not(i%j): break

j = j + 1

if (j > i/j) : print i, " is prime"

i = i + 1

print "Good bye!"

当执行上面的代码，它会产生以下结果：

2 is prime

3 is prime

5 is prime

7 is prime

11 is prime

13 is prime

17 is prime

19 is prime

23 is prime

29 is prime

31 is prime

37 is prime

41 is prime

43 is prime

47 is prime

53 is prime

59 is prime

61 is prime

67 is prime

71 is prime

73 is prime

79 is prime

83 is prime

89 is prime

97 is prime

Good bye!