2

我正在使用这段代码：

def copy_part_of_space(row,column,lenght):
    #Copy String to Presentation Space (15)
    #Prerequisite Connect Presentation Space
    #Prerequisite function: connect_pcomm(presentation_space)    
    function_number = c_int(8)
    data_string = create_string_buffer(lenght*2*2) #number of unicode char *2*2
    lenght = c_int(lenght)
    ps_position = c_int(((row - 1) * 80)+ column)
    foo = hllapi(byref(function_number), data_string, byref(lenght), byref(ps_position))
    data_string.value
    return {{
        0 : 'The host presentation space contents were copied to the application program. The target presentation space was active, and the keyboard was unlocked.',
        1 : 'Your program is not connected to a host session.',
        4 : 'The host presentation space contents were copied. The connected host     presentation space was waiting for host response.',
        5 : 'The host presentation space was copied. The keyboard was locked.',
        9 : 'A system error was encountered.',
        'x' : 'Undocumented error found. Run in circles.',
        }.get(foo, 'x'),data_string.value}

这个想法是从终端复制一些信息；函数需要返回状态信息（使用字典和 0,1,4,5,9,x 参数）和复制的信息 - 使用 data_string.value

为了运行一些测试，我使用了这个使用上述函数的代码：

for a in range(15,22):
    print copy_part_of_space(a,7,8)

这是结果：

   set(['The host presentation space contents were copied to the application program. The target presentation space was active, and the keyboard was unlocked.', '36343581'])
   set(['36343663', 'The host presentation space contents were copied to the application program. The target presentation space was active, and the keyboard was unlocked.'])
   set(['The host presentation space contents were copied to the application program. The target presentation space was active, and the keyboard was unlocked.', '36343708'])
   set(['36344673', 'The host presentation space contents were copied to the application program. The target presentation space was active, and the keyboard was unlocked.'])
   set(['36344740', 'The host presentation space contents were copied to the application program. The target presentation space was active, and the keyboard was unlocked.'])
   set(['The host presentation space contents were copied to the application program. The target presentation space was active, and the keyboard was unlocked.', '36344758'])
   set(['36344869', 'The host presentation space contents were copied to the application program. The target presentation space was active, and the keyboard was unlocked.'])

如您所见，有时我会在从主机应用程序复制内容之前获取状态信息 - 就像第一行一样。

但有时我会得到在状态信息之前复制的信息，比如第二行。

我不熟悉使用dict返回信息，所以我想这可能是一个问题，特别是在我试图返回两个变量的事实混合时。

谁能解释为什么会这样？

我知道dict在传递返回之前我可以简单地使用并将返回信息保存到一个变量中，但我真的认为这是一个更优雅的解决方案——我错了吗？

4

2 回答 2

6

sets 是无序的（或者更好的是，它们的顺序是任意的）。除了使用有序数据类型之外，您无能为力。

例如通过删除set构造函数{...}：

return {
    0 : 'The host presentation space contents were copied to the application program. The target presentation space was active, and the keyboard was unlocked.',
    1 : 'Your program is not connected to a host session.',
    4 : 'The host presentation space contents were copied. The connected host     presentation space was waiting for host response.',
    5 : 'The host presentation space was copied. The keyboard was locked.',
    9 : 'A system error was encountered.',
    'x' : 'Undocumented error found. Run in circles.',
    }.get(foo, 'x'), data_string.value

现在此代码返回一个元组（第一个元素是“错误消息字典”中的查找结果，第二个元素是包含在 中的任何内容data_string.value）。

于 2012-08-02T16:33:52.147 回答
3

您专门返回 a set，它被定义为无序数据类型。也就是说，集合的元素可以按任何顺序返回。集合针对成员资格测试进行了优化 ( if x in set:)。集合就像字典的键：它们可以按任何顺序迭代。

我怀疑对您来说更好的数据类型是元组： return (a, b)

然后结果将始终以相同的顺序排列。

注意文字符号的差异：

  • 字典有冒号来配对项目。: {'a': 'b', 'c': 'd').
  • Set 没有冒号，只是任意排序的项目：{'a', 'b', 'c', 'd'}
  • 元组使用括号：('a', 'b', 'c', 'd')
  • List 使用方括号，并且是可变的：['a', 'b', 'c', 'd']
于 2012-08-02T16:39:04.713 回答