为什么'\ x'在Python中无效? [英] Why is '\x' invalid in Python?

问题描述

我正在试验'\'字符，使用'\ a \ b \ c ...'只是为了自己枚举Python解释为控制字符的字符以及什么.这是我发现的:

I was experimenting with '\' characters, using '\a\b\c...' just to enumerate for myself which characters Python interprets as control characters, and to what. Here's what I found:

\a - BELL
\b - BACKSPACE
\f - FORMFEED
\n - LINEFEED
\r - RETURN
\t - TAB
\v - VERTICAL TAB

我尝试过的大多数其他字符，例如'\ g'，'\ s'等，仅求反斜杠和给定字符的2个字符的字符串.我知道这是故意的，对我来说很有意义.

Most of the other characters I tried, '\g', '\s', etc. just evaluate to the 2-character string of a backslash and the given character. I understand this is intentional, and makes sense to me.

但是'\ x'是一个问题.当我的脚本到达此源代码行时:

But '\x' is a problem. When my script reaches this source line:

val = "\x"

我得到:

ValueError: invalid \x escape

'\ x'有什么特别之处?为什么与其他非转义字符区别对待?

What is so special about '\x'? Why is it treated differently from the other non-escaped characters?

推荐答案

在

注意:

4.与标准C中的不同，仅需要两个十六进制数字.
5.在字符串文字中，十六进制和八进制转义符表示字节 具有给定值；字节不必编码一个字符 在源字符集中.在Unicode文字中，这些转义符表示一个 具有给定值的Unicode字符.

4. Unlike in Standard C, exactly two hex digits are required.
5. In a string literal, hexadecimal and octal escapes denote the byte with the given value; it is not necessary that the byte encodes a character in the source character set. In a Unicode literal, these escapes denote a Unicode character with the given value.

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