Python中return/break/continue用法

break：跳出所在的当前整个循环，到外层代码继续执行。

continue：跳出本次循环，从下一个迭代继续运行循环，内层循环执行完毕，外层代码继续运行。

return：直接返回函数，所有该函数体内的代码（包括循环体）都不会再执行。

用下边的示例代码来解释：

def return_continue_break(type):
    if(not type in ["return", "continue", "break"]):
        print '"type" should be "return, continue, break".'
        return
    for j in range(0, 10):
        for i in range(0, 10):
            print "j_i: %d_%d" %(j, i)
            if(i > 3):
               if(type == "return"):
                   return
               elif(type == "continue"):
                   continue
               else:
                   break
            print "executed!"
 
if __name__ == '__main__':
    return_continue_break("return")
    return_continue_break("break")
    return_continue_break("continue")

return的输出为：

j_i: 0_0
executed!
j_i: 0_1
executed!
j_i: 0_2
executed!
j_i: 0_3
executed!
j_i: 0_4

break的输出为：

j_i: 0_0
executed!
j_i: 0_1
executed!
j_i: 0_2
executed!
j_i: 0_3
executed!
j_i: 0_4
j_i: 1_0
executed!
j_i: 1_1
executed!
j_i: 1_2
executed!
j_i: 1_3
executed!
j_i: 1_4
j_i: 2_0
executed!
j_i: 2_1
executed!
.
.
.
j_i: 8_2
executed!
j_i: 8_3
executed!
j_i: 8_4
j_i: 9_0
executed!
j_i: 9_1
executed!
j_i: 9_2
executed!
j_i: 9_3
executed!
j_i: 9_4

continue的输出为：

j_i: 0_0
executed!
j_i: 0_1
executed!
j_i: 0_2
executed!
j_i: 0_3
executed!
j_i: 0_4
j_i: 0_5
j_i: 0_6
j_i: 0_7
j_i: 0_8
j_i: 0_9
j_i: 1_0
executed!
j_i: 1_1
executed!
j_i: 1_2
executed!
j_i: 1_3
executed!
j_i: 1_4
j_i: 1_5
j_i: 1_6
j_i: 1_7
j_i: 1_8
j_i: 1_9
j_i: 2_0
executed!
.
.
.
j_i: 9_0
executed!
j_i: 9_1
executed!
j_i: 9_2
executed!
j_i: 9_3
executed!
j_i: 9_4
j_i: 9_5
j_i: 9_6
j_i: 9_7
j_i: 9_8
j_i: 9_9