字符串文字前面带有“r”的含义是什么意思？ [重复]

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What exactly do “u” and “r” string flags do, and what are raw string literals? 6 answers
“u”和“r”字符串标志究竟做了什么，以及什么是原始字符串文字？ 6个答案

I first saw it used in building regular expressions across multiple lines as a method argument to re.compile(), so I assumed that r stands for RegEx.

我第一次看到它用于构建跨多行的正则表达式作为re.compile（）的方法参数，所以我假设r代表RegEx。

For example:

例如：

regex = re.compile(
    r'^[A-Z]'
    r'[A-Z0-9-]'
    r'[A-Z]$', re.IGNORECASE
)

So what does r mean in this case? Why do we need it?

那么在这种情况下r意味着什么呢？我们为什么需要它？

2 个解决方案

#1

111

The r means that the string is to be treated as a raw string, which means all escape codes will be ignored.

r表示将字符串视为原始字符串，这意味着将忽略所有转义码。

For an example:

举个例子：

'\n' will be treated as a newline character, while r'\n' will be treated as the characters \ followed by n.

'\ n'将被视为换行符，而r'\ n'将被视为字符\后跟n。

When an 'r' or 'R' prefix is present, a character following a backslash is included in the string without change, and all backslashes are left in the string. For example, the string literal r"\n" consists of two characters: a backslash and a lowercase 'n'. String quotes can be escaped with a backslash, but the backslash remains in the string; for example, r"\"" is a valid string literal consisting of two characters: a backslash and a double quote; r"\" is not a valid string literal (even a raw string cannot end in an odd number of backslashes). Specifically, a raw string cannot end in a single backslash (since the backslash would escape the following quote character). Note also that a single backslash followed by a newline is interpreted as those two characters as part of the string, not as a line continuation.

当存在'r'或'R'前缀时，字符串中包含反斜杠后面的字符不会更改，并且所有反斜杠都保留在字符串中。例如，字符串文字r“\ n”由两个字符组成：反斜杠和小写“n”。字符串引号可以使用反斜杠进行转义，但反斜杠仍保留在字符串中;例如，r“\”“是一个有效的字符串文字，由两个字符组成：反斜杠和双引号; r”\“不是有效的字符串文字（即使原始字符串也不能以奇数个反斜杠结尾）。具体来说，原始字符串不能以单个反斜杠结尾（因为反斜杠会转义后面的引号字符）。另请注意，单行反斜杠后跟换行符被解释为字符串的一部分，而不是行继续。

Source: Python string literals

来源：Python字符串文字

#2

It means that escapes won’t be translated. For example:

这意味着转义不会被转换。例如：

r'\n'

is a string with a backslash followed by the letter n. (Without the r it would be a newline.)

是一个带反斜杠后跟字母n的字符串。（没有r它将是换行符。）

b does stand for byte-string and is used in Python 3, where strings are Unicode by default. In Python 2.x strings were byte-strings by default and you’d use u to indicate Unicode.

b代表字节字符串，在Python 3中使用，其中字符串默认为Unicode。在Python 2.x中，默认情况下字符串是字节字符串，您可以使用u来表示Unicode。

#1

111