Python、Eclipse 中正则表达式字符串的 pep8 警告
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pep8 warning on regex string in Python, Eclipse
提问by alandarev
Why is pep8 complaining on the next string in the code?
为什么 pep8 抱怨代码中的下一个字符串？
import re
re.compile("\d{3}")
The warning I receive:
我收到的警告：
ID:W1401 Anomalous backslash in string: '\d'. String constant might be missing an r prefix.
Can you explain what is the meaning of the message? What do I need to change in the code so that the warning W1401is passed?
你能解释一下消息的含义吗？我需要在代码中更改什么才能通过警告W1401？
The code passes the tests and runs as expected. Moreover \d{3}is a valid regex.
代码通过了测试并按预期运行。此外\d{3}是一个有效的正则表达式。
采纳答案by falsetru
"\d"is same as "\\d"because there's no escape sequence for d. But it is not clear for the reader of the code.
"\d"相同，"\\d"因为 没有转义序列d。但是代码的读者并不清楚。
But, consider \t. "\t"represent tab chracter, while r"\t"represent literal \and tcharacter.
但是，考虑\t. "\t"代表制表符，而r"\t"代表文字\和t字符。
So use raw string when you mean literal \and d:
所以当你的意思是文字\和时使用原始字符串d：
re.compile(r"\d{3}")
or escape backslash explicitly:
或明确转义反斜杠：
re.compile("\d{3}")
回答by userA789
Python is unable to parse '\d'as an escape sequence, that's why it produces a warning.
Python 无法解析'\d'为转义序列，这就是它产生警告的原因。
After that it's passed down to regex parser literally, works fine as an E.S. for regex.
之后它从字面上传递给正则表达式解析器，作为正则表达式的 ES 工作正常。
