Thanks to visit codestin.com
Credit goes to github.com

Skip to content

Commit 3e930ba

Browse files
freddrakefreddrake
committed
Another try at clarifying what goes into and comes out of Unicode objects.
1 parent d8ce87a commit 3e930ba

2 files changed

Lines changed: 46 additions & 31 deletions

File tree

‎Doc/lib/libfuncs.tex‎

Lines changed: 0 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -568,10 +568,6 @@ \section{Built-in Functions \label{built-in-funcs}}
568568
\begin{funcdesc}{len}{s}
569569
Return the length (the number of items) of an object. The argument
570570
may be a sequence (string, tuple or list) or a mapping (dictionary).
571-
In the case of Unicode strings, \function{len()} returns the number
572-
of storage units, not abstract characters. In particular, when a
573-
surrogate pair is encountered, each component of the pair is counted
574-
as a separate character.
575571
\end{funcdesc}
576572

577573
\begin{funcdesc}{list}{\optional{sequence}}

‎Doc/ref/ref2.tex‎

Lines changed: 46 additions & 27 deletions
Original file line numberDiff line numberDiff line change
@@ -410,29 +410,48 @@ \subsection{String literals\label{strings}}
410410
\index{Standard C}
411411
\index{C}
412412

413-
\begin{tableii}{l|l}{code}{Escape Sequence}{Meaning}
414-
\lineii{\e\var{newline}} {Ignored}
415-
\lineii{\e\e} {Backslash (\code{\e})}
416-
\lineii{\e'} {Single quote (\code{'})}
417-
\lineii{\e"} {Double quote (\code{"})}
418-
\lineii{\e a} {\ASCII{} Bell (BEL)}
419-
\lineii{\e b} {\ASCII{} Backspace (BS)}
420-
\lineii{\e f} {\ASCII{} Formfeed (FF)}
421-
\lineii{\e n} {\ASCII{} Linefeed (LF)}
422-
\lineii{\e N\{\var{name}\}}
423-
{Character named \var{name} in the Unicode database (Unicode only)}
424-
\lineii{\e r} {\ASCII{} Carriage Return (CR)}
425-
\lineii{\e t} {\ASCII{} Horizontal Tab (TAB)}
426-
\lineii{\e u\var{xxxx}} {Character with 16-bit hex value \var{xxxx} (Unicode only)}
427-
\lineii{\e U\var{xxxxxxxx}}{Character with 32-bit hex value \var{xxxxxxxx} (Unicode only)}
428-
\lineii{\e v} {\ASCII{} Vertical Tab (VT)}
429-
\lineii{\e\var{ooo}} {\ASCII{} character with octal value \var{ooo}}
430-
\lineii{\e x\var{hh}} {\ASCII{} character with hex value \var{hh}}
431-
\end{tableii}
413+
\begin{tableiii}{l|l|c}{code}{Escape Sequence}{Meaning}{Notes}
414+
\lineiii{\e\var{newline}} {Ignored}{}
415+
\lineiii{\e\e} {Backslash (\code{\e})}{}
416+
\lineiii{\e'} {Single quote (\code{'})}{}
417+
\lineiii{\e"} {Double quote (\code{"})}{}
418+
\lineiii{\e a} {\ASCII{} Bell (BEL)}{}
419+
\lineiii{\e b} {\ASCII{} Backspace (BS)}{}
420+
\lineiii{\e f} {\ASCII{} Formfeed (FF)}{}
421+
\lineiii{\e n} {\ASCII{} Linefeed (LF)}{}
422+
\lineiii{\e N\{\var{name}\}}
423+
{Character named \var{name} in the Unicode database (Unicode only)}{}
424+
\lineiii{\e r} {\ASCII{} Carriage Return (CR)}{}
425+
\lineiii{\e t} {\ASCII{} Horizontal Tab (TAB)}{}
426+
\lineiii{\e u\var{xxxx}}
427+
{Character with 16-bit hex value \var{xxxx} (Unicode only)}{(1)}
428+
\lineiii{\e U\var{xxxxxxxx}}
429+
{Character with 32-bit hex value \var{xxxxxxxx} (Unicode only)}{(2)}
430+
\lineiii{\e v} {\ASCII{} Vertical Tab (VT)}{}
431+
\lineiii{\e\var{ooo}} {\ASCII{} character with octal value \var{ooo}}{(3)}
432+
\lineiii{\e x\var{hh}} {\ASCII{} character with hex value \var{hh}}{(4)}
433+
\end{tableiii}
432434
\index{ASCII@\ASCII}
433435

434-
As in Standard C, up to three octal digits are accepted. However,
435-
exactly two hex digits are taken in hex escapes.
436+
\noindent
437+
Notes:
438+
439+
\begin{itemize}
440+
\item[(1)]
441+
Individual code units which form parts of a surrogate pair can be
442+
encoded using this escape sequence.
443+
\item[(2)]
444+
Any Unicode character can be encoded this way, but characters
445+
outside the Basic Multilingual Plane (BMP) will be encoded using a
446+
surrogate pair if Python is compiled to use 16-bit code units (the
447+
default). Individual code units which form parts of a surrogate
448+
pair can be encoded using this escape sequence.
449+
\item[(3)]
450+
As in Standard C, up to three octal digits are accepted.
451+
\item[(4)]
452+
Unlike in Standard C, at most two hex digits are accepted.
453+
\end{itemize}
454+
436455

437456
Unlike Standard \index{unrecognized escape sequence}C,
438457
all unrecognized escape sequences are left in the string unchanged,
@@ -460,12 +479,12 @@ \subsection{String literals\label{strings}}
460479
When an \character{r} or \character{R} prefix is used in conjunction
461480
with a \character{u} or \character{U} prefix, then the \code{\e uXXXX}
462481
escape sequence is processed while \emph{all other backslashes are
463-
left in the string}. For example, the string literal \code{ur"\e
464-
u0062\e n"} consists of three Unicode characters: `LATIN SMALL LETTER
465-
B', `REVERSE SOLIDUS', and `LATIN SMALL LETTER N'. Backslashes can be
466-
escaped with a preceding backslash; however, both remain in the
467-
string. As a result, \code{\e uXXXX} escape sequences are only
468-
recognized when there are an odd number of backslashes.
482+
left in the string}. For example, the string literal
483+
\code{ur"\e{}u0062\e n"} consists of three Unicode characters: `LATIN
484+
SMALL LETTER B', `REVERSE SOLIDUS', and `LATIN SMALL LETTER N'.
485+
Backslashes can be escaped with a preceding backslash; however, both
486+
remain in the string. As a result, \code{\e uXXXX} escape sequences
487+
are only recognized when there are an odd number of backslashes.
469488

470489
\subsection{String literal concatenation\label{string-catenation}}
471490

0 commit comments

Comments
 (0)