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| -rw-r--r-- | Doc/tut/tut.tex | 62 |
1 files changed, 40 insertions, 22 deletions
diff --git a/Doc/tut/tut.tex b/Doc/tut/tut.tex index 8a47b22..4720fed 100644 --- a/Doc/tut/tut.tex +++ b/Doc/tut/tut.tex @@ -772,17 +772,17 @@ u'Hello World !' \end{verbatim} The escape sequence \code{\e u0020} indicates to insert the Unicode -character with the HEX ordinal 0x0020 (the space character) at the +character with the ordinal value 0x0020 (the space character) at the given position. Other characters are interpreted by using their respective ordinal -value directly as Unicode ordinal. Due to the fact that the lower 256 -Unicode are the same as the standard Latin-1 encoding used in many -western countries, the process of entering Unicode is greatly -simplified. +values directly as Unicode ordinals. If you have literal strings +in the standard Latin-1 encoding that is used in many Western countries, +you will find it convenient that the lower 256 characters +of Unicode are the same as the 256 characters of Latin-1. -For experts, there is also a raw mode just like for normal -strings. You have to prepend the string with a small 'r' to have +For experts, there is also a raw mode just like the one for normal +strings. You have to prefix the opening quote with 'ur' to have Python use the \emph{Raw-Unicode-Escape} encoding. It will only apply the above \code{\e uXXXX} conversion if there is an uneven number of backslashes in front of the small 'u'. @@ -801,32 +801,50 @@ Apart from these standard encodings, Python provides a whole set of other ways of creating Unicode strings on the basis of a known encoding. -The built-in function \function{unicode()}\bifuncindex{unicode} provides access -to all registered Unicode codecs (COders and DECoders). Some of the -more well known encodings which these codecs can convert are -\emph{Latin-1}, \emph{ASCII}, \emph{UTF-8} and \emph{UTF-16}. The latter two -are variable-length encodings which store Unicode characters -in blocks of 8 or 16 bits. To print a Unicode string or write it to a file, -you must convert it to a string with the \method{encode()} method. +The built-in function \function{unicode()}\bifuncindex{unicode} provides +access to all registered Unicode codecs (COders and DECoders). Some of +the more well known encodings which these codecs can convert are +\emph{Latin-1}, \emph{ASCII}, \emph{UTF-8}, and \emph{UTF-16}. +The latter two are variable-length encodings that store each Unicode +character in one or more bytes. The default encoding is +normally set to ASCII, which passes through characters in the range +0 to 127 and rejects any other characters with an error. +When a Unicode string is printed, written to a file, or converted +with \function{str()}, conversion takes place using this default encoding. + +\begin{verbatim} +>>> u"abc" +u'abc' +>>> str(u"abc") +'abc' +>>> u"äöü" +u'\xe4\xf6\xfc' +>>> str(u"äöü") +Traceback (most recent call last): + File "<stdin>", line 1, in ? +UnicodeError: ASCII encoding error: ordinal not in range(128) +\end{verbatim} + +To convert a Unicode string into an 8-bit string using a specific +encoding, Unicode objects provide an \function{encode()} method +that takes one argument, the name of the encoding. Lowercase names +for encodings are preferred. \begin{verbatim} ->>> u"äöü" -u'\344\366\374' ->>> u"äöü".encode('UTF-8') -'\303\244\303\266\303\274' +>>> u"äöü".encode('utf-8') +'\xc3\xa4\xc3\xb6\xc3\xbc' \end{verbatim} If you have data in a specific encoding and want to produce a corresponding Unicode string from it, you can use the -\function{unicode()} function with the encoding name as second +\function{unicode()} function with the encoding name as the second argument. \begin{verbatim} ->>> unicode('\303\244\303\266\303\274','UTF-8') -u'\344\366\374' +>>> unicode('\xc3\xa4\xc3\xb6\xc3\xbc', 'utf-8') +u'\xe4\xf6\xfc' \end{verbatim} - \subsection{Lists \label{lists}} Python knows a number of \emph{compound} data types, used to group |