python原始字符串r_“ u”和“ r”字符串标志的作用是什么？Python中的原始字符串文字是什么？...

曾经终败给现在 2023-03-05 05:28 50阅读 0赞

python原始字符串r

The prefix of **'u'** in a string denotes the value of type Unicode rather than str. However, the Unicode strings are no longer used in Python3. The prefix of **'u'** in a string denotes the value of type Unicode rather than str. However, the Unicode strings are no longer used in Python3.

字符串中的**'u'**前缀表示Unicode类型的值，而不是str。 但是，Python3中不再使用Unicode字符串。 字符串中的**'u'**前缀表示Unicode类型的值，而不是str。 但是，Python3中不再使用Unicode字符串。

In Python2, if we type a string literal without **'u'** in front, we get the old str type which stores 8-bit characters, and with **'u'** in front we get the newer Unicode type that can store any Unicode character.

在Python2中，如果键入的字符串文字前面没有**'u'** ，我们将得到存储8位字符的旧str类型，而前面带有**'u'**的我们将获得可以存储任何Unicode字符的较新的Unicode类型。

Additionally adding **'r'** doesn't change the type of the literal, just changes how the string literal is interpreted. Without the **'r'** backlashes (/) are treated as escape characters. With **'r'** (/) are treated as literal.

另外，添加**'r'**不会改变文字的类型，只是改变字符串文字的解释方式。 没有**'r'的**反斜杠(/)被视为转义字符。 用**'r'** (/)视为文字。

## 原始字符串 **(**Raw strings**)** ##

Prefixing the string with **'r'** makes the string literal a **'raw string'**. Python raw string treats backslash (**\\**) as a literal character, which makes it useful when we want to have a string that contains backslash and don’t want it to be treated as an escape character.

给字符串加上**'r'**前缀会使字符串文字成为**'raw string'** 。 Python原始字符串将反斜杠( **\\** )视为文字字符，当我们希望包含反斜杠的字符串并且不希望将其视为转义字符时，它非常有用。

Consider the below example, where (**\\**) has a special meaning.

考虑下面的示例，其中( **\\** )具有特殊含义。

s='Hi\nHello'
    print(s)
    
    r=r'Hi\nHello'
    print(r)

**Output**

**输出量**

Hi
    Hello
    Hi\nHello

Consider the below example, where (\\) doesn't have special meaning,

考虑下面的示例，其中(\\)没有特殊含义，

s='Hi\xHello'

**Output**

**输出量**

File "main.py", line 1
        s='Hi\xHello'
          ^
    SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \xXX escape

s=r'Hi\xHello'
    print(s)

**Output**

**输出量**

Hi\xHello

> 翻译自: [https://www.includehelp.com/python/what-exactly-do-u-and-r-string-flags-do-and-what-are-raw-string-literals.aspx][https_www.includehelp.com_python_what-exactly-do-u-and-r-string-flags-do-and-what-are-raw-string-literals.aspx]

python原始字符串r

[https_www.includehelp.com_python_what-exactly-do-u-and-r-string-flags-do-and-what-are-raw-string-literals.aspx]: https://www.includehelp.com/python/what-exactly-do-u-and-r-string-flags-do-and-what-are-raw-string-literals.aspx