如何在f字符串中使用换行符'\ n'格式化Python 3.6中的输出? [英] How to use newline '\n' in f-string to format output in Python 3.6?

问题描述

我想知道如何使用f字符串以Python的方式格式化这种情况:

I would like to know how to format this case in a Pythonic way with f-strings:

names = ['Adam', 'Bob', 'Cyril']
text = f"Winners are:\n{'\n'.join(names)}"
print(text)

问题是'\'不能在f字符串的{...}表达式部分内使用. 预期输出:

The problem is that '\' cannot be used inside the {...} expression portions of an f-string. Expected output:

Winners are:
Adam
Bob
Cyril

推荐答案

您不能.反斜杠不能出现在花括号{}内；这样做会导致SyntaxError:

You can't. Backslashes cannot appear inside the curly braces {}; doing so results in a SyntaxError:

>>> f'{\}'
SyntaxError: f-string expression part cannot include a backslash

在 PEP 中为f-字符串:

反斜杠可能不会出现在f字符串的表达式部分[...]

Backslashes may not appear inside the expression portions of f-strings, [...]

一个选项是将'\n'命名为一个名称，然后在f -string内的名称上添加.join；也就是说，不使用文字:

One option is assinging '\n' to a name and then .join on that inside the f-string; that is, without using a literal:

names = ['Adam', 'Bob', 'Cyril']
nl = '\n'
text = f"Winners are:{nl}{nl.join(names)}"
print(text)

结果:

Winners are:
Adam
Bob
Cyril

由@wim指定的另一个选项是使用chr(10)来获取返回的\n，然后在该处加入. f"Winners are:\n{chr(10).join(names)}"

Another option, as specified by @wim, is to use chr(10) to get \n returned and then join there. f"Winners are:\n{chr(10).join(names)}"

当然，另一个方法是事先到达'\n'.join，然后相应地添加名称:

Yet another, of course, is to '\n'.join beforehand and then add the name accordingly:

n = "\n".join(names)
text = f"Winners are:\n{n}"

这将导致相同的输出.

这是f -strings和str.format之间的细微差别之一.在后者中，只要解压缩了包含这些键的相应古怪字典，您就可以始终使用标点符号:

This is one of the small differences between f-strings and str.format. In the latter, you can always use punctuation granted that a corresponding wacky dict is unpacked that contains those keys:

>>> "{\\} {*}".format(**{"\\": 'Hello', "*": 'World!'})
"Hello World!"

_{(请不要这样做.)}

在前一种情况下，标点符号是不允许的，因为您没有使用它们的标识符.

In the former, punctuation isn't allowed because you can't have identifiers that use them.

此外:我肯定会选择print或format，因为其他答案也可以作为替代选择.我给出的选项仅在必须出于某种原因使用f字符串的情况下适用.

Aside: I would definitely opt for print or format, as the other answers suggest as an alternative. The options I've given only apply if you must for some reason use f-strings.

仅仅是因为有些新事物，并不意味着您应该尝试使用它做一切；-)

Just because something is new, doesn't mean you should try and do everything with it ;-)

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