如何在 f-string 中使用换行符 '\n' 来格式化 Python 3.6 中的输出？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/44780357/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to use newline '\n' in f-string to format output in Python 3.6?
提问by malmed
I would like to know how to format this case in a Pythonic way with f-strings:
我想知道如何使用 f-strings 以 Pythonic 的方式格式化这个案例：
names = ['Adam', 'Bob', 'Cyril']
text = f"Winners are:\n{'\n'.join(names)}"
print(text)
The problem is that '\'cannot be used inside the {...}expression portions of an f-string.
Expected output:
问题是'\'不能在{...}f 字符串的表达式部分内使用。预期输出：
Winners are:
Adam
Bob
Cyril
回答by Dimitris Fasarakis Hilliard
You can't. Backslashes cannot appear inside the curly braces {}; doing so results in a SyntaxError:
你不能。反斜杠不能出现在花括号内{}；这样做会导致SyntaxError：
>>> f'{\}'
SyntaxError: f-string expression part cannot include a backslash
This is specified in the PEPfor f-strings:
这是在PEP 中为 f 字符串指定的：
Backslashes may not appear inside the expression portions of f-strings, [...]
反斜杠可能不会出现在 f 字符串的表达式部分中，[...]
One option is assinging '\n'to a name and then .joinon that inside the f-string; that is, without using a literal:
一种选择是分配'\n'一个名称，然后.join在f-string 中分配名称；也就是说，不使用文字：
names = ['Adam', 'Bob', 'Cyril']
nl = '\n'
text = f"Winners are:{nl}{nl.join(names)}"
print(text)
Results in:
结果是：
Winners are:
Adam
Bob
Cyril
Another option, as specified by @wim, is to use chr(10)to get \nreturned and then join there. f"Winners are:\n{chr(10).join(names)}"
另一种选择，如@wim规定，就是用chr(10)得到\n恢复，然后加入那里。f"Winners are:\n{chr(10).join(names)}"
Yet another, of course, is to '\n'.joinbeforehand and then add the name accordingly:
当然，还有一个是'\n'.join预先添加名称，然后相应地添加名称：
n = "\n".join(names)
text = f"Winners are:\n{n}"
which results in the same output.
这导致相同的输出。
Note:
笔记：
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:
这是f-strings 和str.format. 在后者中，您始终可以使用标点符号，只要解压缩包含这些键的相应古怪字典：
>>> "{\} {*}".format(**{"\": 'Hello', "*": 'World!'})
"Hello World!"
(Please don't do this.)
（请不要这样做。）
In the former, punctuation isn't allowed because you can't have identifiers that use them.
在前者中，不允许使用标点符号，因为您不能拥有使用它们的标识符。
Aside: I would definitely opt for printor format, as the other answers suggest as an alternative. The options I've given only apply if you mustfor some reason use f-strings.
旁白：我肯定会选择printor format，正如其他答案所建议的那样。我给出的选项仅适用于出于某种原因必须使用 f 字符串的情况。
Just because something is new, doesn't mean you should try and do everything with it ;-)
仅仅因为某些东西是新的，并不意味着你应该尝试用它做所有事情;-)
回答by Eugene Yarmash
You don't need f-strings or other formatters to print a list of strings with a separator. Just use the sepkeyword argument to print():
您不需要 f 字符串或其他格式化程序来打印带有分隔符的字符串列表。只需使用sep关键字参数print()：
names = ['Adam', 'Bob', 'Cyril']
print('Winners are:', *names, sep='\n')
Output:
输出：
Winners are:
Adam
Bob
Cyril
That said, using str.join()/str.format()here would arguably be simpler and more readable than any f-string workaround:
也就是说，在这里使用str.join()/str.format()可以说比任何 f-string 解决方法更简单、更具可读性：
print('\n'.join(['Winners are:', *names]))
print('Winners are:\n{}'.format('\n'.join(names)))
回答by Chris_Rands
You can't use backslashes in f-strings as others have said, but you could step around this using os.linesep(although note this won't be \non all platforms, and is not recommended unless reading/writing binary files; see Rick'scomments):
您不能像其他人所说的那样在 f 字符串中使用反斜杠，但您可以使用os.linesep（尽管请注意这不会\n在所有平台上使用，除非读取/写入二进制文件，否则不推荐使用；请参阅Rick 的评论）：
>>> import os
>>> names = ['Adam', 'Bob', 'Cyril']
>>> print(f"Winners are:\n{os.linesep.join(names)}")
Winners are:
Adam
Bob
Cyril
Or perhaps in a less readable way, but guaranteed to be \n, with chr():
或者也许以一种不太可读的方式，但保证是\n，与chr()：
>>> print(f"Winners are:\n{chr(10).join(names)}")
Winners are:
Adam
Bob
Cyril
回答by Rick supports Monica
The other answers give ideas for how to put the newline character into a f-string field. However, I would argue that for the example the OP gave (which may or may not be indicative of OP's actual use case), none of these ideas should actually be used.
其他答案给出了如何将换行符放入 f 字符串字段的想法。但是，我认为对于 OP 给出的示例（这可能表示也可能不表示 OP 的实际用例），实际上不应使用这些想法中的任何一个。
The entire point of using f-strings is increasing code readability. There is nothing you can do with f-strings that you cannot do with format. Consider carefully whether there is anything more readableabout this (if you could do it):
使用 f-strings 的全部意义在于提高代码的可读性。使用 f-strings 没有什么是你无法使用的format。仔细考虑是否有任何关于此的更具可读性的内容（如果你能做到的话）：
f"Winners are:\n{'\n'.join(names)}"
...or this:
...或这个：
newline = '\n'
f"Winners are:\n{newline.join(names)}"
...or this:
...或这个：
"Winners are:\n{chr(10).join(names)}"
vs. this:
与这个：
"Winners are:\n{}".format('\n'.join(names))
The last way is at least as readable, if not more so.
最后一种方法至少是可读的，如果不是更多的话。
In short: don't use a hammer when you need a screwdriver just because you have a shiny new one. Code is read much more often than it is written.
简而言之：当你需要一把螺丝刀时，不要仅仅因为你有一把闪亮的新螺丝刀就使用锤子。代码的阅读次数远多于编写次数。
For other use cases, yes, it's possible the chr(10)idea or newlineidea may be appropriate. But not for the one given.
对于其他用例，是的，这个chr(10)想法或newline想法可能是合适的。但不是给定的。
