为什么这个字典定义会引发语法错误？ [复制]

可能的重复：
lVals = [1, 08, 2011] 抛出异常有什么原因吗？

我正在定义一个字典，将天数映射到各自的单词。由于某种原因，以下代码引发“SyntaxError：无效标记”并突出显示“08”

days = {01:"first", 02:"second", 03:"third", 04:"fourth", 05:"fifth", 06:"sixth", 07:"seventh", 08:"eighth", 09:"nineth", 10:"tenth", 
    11:"eleventh", 12:"twelvth", 13:"thirteenth", 14:"fourteenth", 15:"fifteenth", 16:"sixteenth", 17:"seventeenth", 18:"eighteenth",
    19:"nineteenth", 20:"twentieth", 21:"twenty-first", 22:"twenty-second", 23:"twenty-third", 24:"twenty-fourth", 25:"twenty-fifth",
    26:"twenty-sixth", 27:"twenty-seventh", 28:"twenty-eighth", 29:"twenty-nineth", 30:"thirtieth", 31:"thirty-first"}

修改代码，使 08 和 09 变为 98 和 99 可以阻止任何错误，如下代码所示：

days = {01:"first", 02:"second", 03:"third", 04:"fourth", 05:"fifth", 06:"sixth", 07:"seventh", 98:"eighth", 99:"nineth", 10:"tenth", 
    11:"eleventh", 12:"twelvth", 13:"thirteenth", 14:"fourteenth", 15:"fifteenth", 16:"sixteenth", 17:"seventeenth", 18:"eighteenth",
    19:"nineteenth", 20:"twentieth", 21:"twenty-first", 22:"twenty-second", 23:"twenty-third", 24:"twenty-fourth", 25:"twenty-fifth",
    26:"twenty-sixth", 27:"twenty-seventh", 28:"twenty-eighth", 29:"twenty-nineth", 30:"thirtieth", 31:"thirty-first"}

输出变为：

{1: 'first', 2: 'second', 3: 'third', 4: 'fourth', 5: 'fifth', 6: 'sixth', 7: 'seventh', 10: 'tenth', 11: 'eleventh', 12: 'twelvth', 13: 'thirteenth', 14: 'fourteenth', 15: 'fifteenth', 16: 'sixteenth', 17: 'seventeenth', 18: 'eighteenth', 19: 'nineteenth', 20: 'twentieth', 21: 'twenty-first', 22: 'twenty-second', 23: 'twenty-third', 24: 'twenty-fourth', 25: 'twenty-fifth', 26: 'twenty-sixth', 27: 'twenty-seventh', 28: 'twenty-eighth', 29: 'twenty-nineth', 30: 'thirtieth', 31: 'thirty-first', 98: 'eighth', 99: 'nineth'}

之前错误的键已移动到字典的末尾。

非常感谢发现这里发生的事情的人，

James

号码0是整数文字的前缀，表示它是 python 中的八进制数。

...正如我不小心遗漏的那样，正如 @larsmans 在他的评论中如此善意地指出的那样，将数字限制为仅包含数字0通过7，不包括8 and 9.

不过，同样值得注意的是，这是 Python 2.x 中的语法 - 从 Python 3.0 开始它已更改，表面上是出于您来到这里的确切原因。PEP 3127包含更改的详细信息。

最相关的一点：

目前几乎所有流行的计算机语言，包括 C/C++、Java、Perl 和 JavaScript，都将带有前导零的数字序列视为八进制数。将这些数字视为十进制的支持者有一个非常有效的观点 - [...]整个非计算机世界几乎只使用十进制数字。