Python编程语言允许在一个循环中使用另一个循环。以下部分显示了几个示例来说明这一概念。
nested loops - 语法
for iterating_var in sequence: for iterating_var in sequence: statements(s) statements(s)
Python编程语言中嵌套的WHILE LOOP语句的语法如下所示:-
while expression: while expression: statement(s) statement(s)
关于循环嵌套的最后一个注意事项是，您可以将任何类型的循环放在任何其他类型的循环中。如，for循环可以在while循环中，反之亦然。
nested loops - 示例
下面的程序使用嵌套的FOR循环来查找从2到100-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!"
执行上述代码时，将生成以下输出-
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!
