字符串包含“%s"时的 Python 字符串格式化不逃避 [英] Python string formatting when string contains "%s" without escaping

问题描述

格式化字符串时，我的字符串可能包含我不希望转换的模 "%".我可以转义字符串并将每个 "%" 更改为 "%%" 作为解决方法.

When formatting a string, my string may contain a modulo "%" that I do not wish to have converted. I can escape the string and change each "%" to "%%" as a workaround.

例如，

'Day old bread, 50%% sale %s' % 'today!'  

输出:

'Day old bread, 50% sale today'

但是除了逃避还有其他选择吗?我希望使用 dict 可以让 Python 忽略任何非关键字转换.
例如，

But are there any alternatives to escaping? I was hoping that using a dict would make it so Python would ignore any non-keyword conversions.
e.g.,

'Day old bread, 50% sale %(when)s' % {'when': 'today'}  

但 Python 仍然看到第一个模 % 并给出:

but Python still sees the first modulo % and gives a:

TypeError: not enough arguments for format string

推荐答案

您可以(并且应该)使用 新字符串 .format() 方法(如果您有 Python 2.6 或更高版本):

You could (and should) use the new string .format() method (if you have Python 2.6 or higher) instead:

"Day old bread, 50% sale {0}".format("today")

可以在此处找到手册.

文档还说旧的 % 格式最终将从语言中删除，尽管这肯定需要一些时间.新的格式化方法更强大，所以这是一件好事.

The docs also say that the old % formatting will eventually be removed from the language, although that will surely take some time. The new formatting methods are way more powerful, so that's a Good Thing.

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