反斜杠:

s = "this is my really, really, really, really, really, really" +  \
    "really long string that I'd like to shorten."

或者用括号括起来:

s = ("this is my really, really, really, really, really, really" + 
    "really long string that I'd like to shorten.")

message = f"Variable : child({type(child)}) -> is not of"\
        " type Node."

这个语法适合我。注意第二个语句的缩进，它应该缩进正确。

我以前用过textwrap.dedent。这有点麻烦，所以我现在更喜欢行延续，但如果你真的想要块缩进，我认为这很好。

示例代码(其中trim是去掉带有切片的第一个'\n'):

import textwrap as tw
x = """\
       This is a yet another test.
       This is only a test"""
print(tw.dedent(x))

解释:

Dedent根据新行前第一行文本中的空白计算缩进。如果你想调整它，你可以使用re模块轻松地重新实现它。

这种方法有局限性，很长的行可能仍然比你想要的长，在这种情况下，其他方法连接字符串更适合。

如果你必须插入一个长字符串文字，并希望flake8关闭，你可以使用它的关闭指令。例如，在一个测试例程中，我定义了一些假的CSV输入。我发现把它分成更多行会非常混乱，所以我决定添加一个# noqa: E501，如下所示:

csv_test_content = """"STATION","DATE","SOURCE","LATITUDE","LONGITUDE","ELEVATION","NAME","REPORT_TYPE","CALL_SIGN","QUALITY_CONTROL","WND","CIG","VIS","TMP","DEW","SLP","AA1","AA2","AY1","AY2","GF1","MW1","REM"
"94733099999","2019-01-03T22:00:00","4","-32.5833333","151.1666666","45.0","SINGLETON STP, AS","FM-12","99999","V020","050,1,N,0010,1","22000,1,9,N","025000,1,9,9","+0260,1","+0210,1","99999,9","24,0000,9,1",,"0,1,02,1","0,1,02,1","01,99,1,99,9,99,9,99999,9,99,9,99,9","01,1","SYN05294733 11/75 10502 10260 20210 60004 70100 333 70000="
"94733099999","2019-01-04T04:00:00","4","-32.5833333","151.1666666","45.0","SINGLETON STP, AS","FM-12","99999","V020","090,1,N,0021,1","22000,1,9,N","025000,1,9,9","+0378,1","+0172,1","99999,9","06,0000,9,1",,"0,1,02,1","0,1,02,1","03,99,1,99,9,99,9,99999,9,99,9,99,9","03,1","SYN04294733 11/75 30904 10378 20172 60001 70300="
"94733099999","2019-01-04T22:00:00","4","-32.5833333","151.1666666","45.0","SINGLETON STP, AS","FM-12","99999","V020","290,1,N,0057,1","99999,9,9,N","020000,1,9,9","+0339,1","+0201,1","99999,9","24,0000,9,1",,"0,1,02,1","0,1,02,1",,"02,1","SYN05294733 11970 02911 10339 20201 60004 70200 333 70000="
"94733099999","2019-01-05T22:00:00","4","-32.5833333","151.1666666","45.0","SINGLETON STP, AS","FM-12","99999","V020","200,1,N,0026,1","99999,9,9,N","000100,1,9,9","+0209,1","+0193,1","99999,9","24,0004,3,1",,"1,1,02,1","1,1,02,1","08,99,1,99,9,99,9,99999,9,99,9,99,9","51,1","SYN05294733 11/01 82005 10209 20193 69944 75111 333 70004="
"94733099999","2019-01-08T04:00:00","4","-32.5833333","151.1666666","45.0","SINGLETON STP, AS","FM-12","99999","V020","070,1,N,0026,1","22000,1,9,N","025000,1,9,9","+0344,1","+0213,1","99999,9","06,0000,9,1",,"2,1,02,1","2,1,02,1","04,99,1,99,9,99,9,99999,9,99,9,99,9","02,1","SYN04294733 11/75 40705 10344 20213 60001 70222="
"""  # noqa: E501

因为相邻的字符串常量是自动连接的，你可以这样编码:

s = ("this is my really, really, really, really, really, really, "  
     "really long string that I'd like to shorten.")

注意没有加号，我在示例的格式后面添加了额外的逗号和空格。

就我个人而言，我不喜欢反斜杠，我记得在某个地方读到过，它的使用实际上是被反对的，而支持这种更明确的形式。记住“显式优于隐式”。

我认为反斜杠不太清楚，也不太有用，因为这实际上是转义换行符。如果需要的话，不能在它后面加上行结束注释。可以通过串接字符串常量来实现:

s = ("this is my really, really, really, really, really, really, " # comments ok
     "really long string that I'd like to shorten.")

我使用谷歌搜索“python行长”，它返回PEP8链接作为第一个结果，但也链接到另一个关于这个主题的StackOverflow帖子:“为什么python PEP-8应该指定79个字符的最大行长?”

另一个好的搜索短语是“python line continuation”。

我觉得你问题中最重要的一个词是“suggest”。

编码标准是很有趣的东西。通常他们提供的指导在编写时有很好的基础(例如，大多数终端无法在一行上显示> 80个字符)，但随着时间的推移，它们在功能上变得过时了，但仍然被严格遵守。我猜您在这里需要做的是权衡“破坏”特定建议与代码的可读性和可维护性之间的相对优点。

抱歉，这并不能直接回答你的问题。