Python打印方式：使用“format”或percent form？

Question

在Python中，生成格式化输出的方式似乎有两种：

user = "Alex"
number = 38746
print("%s asked %d questions on stackoverflow.com" % (user, number))
print("{0} asked {1} questions on stackoverflow.com".format(user, number))

有没有一种方法比另一种更好？它们相等吗，有什么区别？应该使用什么形式，尤其是Python3？

Answer 1

The docs假设新代码首选format方法。不过，目前没有删除%格式的计划。

Answer 2

在Python2.6中引入了.format

如果您需要与早期的Python向后兼容，那么应该使用%

对于Python3和更新版本，应该使用.format来确定

.format比%更强大。将%移植到.format很容易，但另一种方法可能并不简单

Answer 3

使用format方法，特别是当您关心Python 3和未来时。来自the documentation：

The formatting operations described here are modelled on C's printf() syntax. They only support formatting of certain builtin types. The use of a binary operator means that care may be needed in order to format tuples and dictionaries correctly. As the new :ref:string-formatting syntax is more flexible and handles tuples and dictionaries naturally, it is recommended for new code. However, there are no current plans to deprecate printf-style formatting.