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Convert all print statements in the docs.
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Georg Brandl
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71 changed files with 351 additions and 388 deletions
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@ -7,6 +7,12 @@
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This HOWTO discusses Python's support for Unicode, and explains various problems
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that people commonly encounter when trying to work with Unicode.
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.. XXX fix it
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.. warning::
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This HOWTO has not yet been updated for Python 3000's string object changes.
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Introduction to Unicode
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=======================
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@ -122,8 +128,8 @@ The first encoding you might think of is an array of 32-bit integers. In this
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representation, the string "Python" would look like this::
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P y t h o n
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0x50 00 00 00 79 00 00 00 74 00 00 00 68 00 00 00 6f 00 00 00 6e 00 00 00
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
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0x50 00 00 00 79 00 00 00 74 00 00 00 68 00 00 00 6f 00 00 00 6e 00 00 00
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
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This representation is straightforward but using it presents a number of
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problems.
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@ -181,7 +187,7 @@ UTF-8.) UTF-8 uses the following rules:
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between 128 and 255.
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3. Code points >0x7ff are turned into three- or four-byte sequences, where each
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byte of the sequence is between 128 and 255.
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UTF-8 has several convenient properties:
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1. It can handle any Unicode code point.
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@ -256,7 +262,7 @@ characters greater than 127 will be treated as errors::
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>>> unicode('abcdef' + chr(255))
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Traceback (most recent call last):
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File "<stdin>", line 1, in ?
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UnicodeDecodeError: 'ascii' codec can't decode byte 0xff in position 6:
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UnicodeDecodeError: 'ascii' codec can't decode byte 0xff in position 6:
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ordinal not in range(128)
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The ``errors`` argument specifies the response when the input string can't be
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@ -268,7 +274,7 @@ Unicode result). The following examples show the differences::
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>>> unicode('\x80abc', errors='strict')
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Traceback (most recent call last):
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File "<stdin>", line 1, in ?
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UnicodeDecodeError: 'ascii' codec can't decode byte 0x80 in position 0:
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UnicodeDecodeError: 'ascii' codec can't decode byte 0x80 in position 0:
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ordinal not in range(128)
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>>> unicode('\x80abc', errors='replace')
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u'\ufffdabc'
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@ -354,7 +360,7 @@ interprets the string using the given encoding::
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>>> u2 = utf8_version.decode('utf-8') # Decode using UTF-8
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>>> u == u2 # The two strings match
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True
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The low-level routines for registering and accessing the available encodings are
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found in the :mod:`codecs` module. However, the encoding and decoding functions
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returned by this module are usually more low-level than is comfortable, so I'm
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@ -366,8 +372,8 @@ covered here. Consult the Python documentation to learn more about this module.
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The most commonly used part of the :mod:`codecs` module is the
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:func:`codecs.open` function which will be discussed in the section on input and
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output.
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Unicode Literals in Python Source Code
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--------------------------------------
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@ -385,10 +391,10 @@ arbitrary code point. Octal escapes can go up to U+01ff, which is octal 777.
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>>> s = u"a\xac\u1234\u20ac\U00008000"
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^^^^ two-digit hex escape
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^^^^^^ four-digit Unicode escape
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^^^^^^ four-digit Unicode escape
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^^^^^^^^^^ eight-digit Unicode escape
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>>> for c in s: print ord(c),
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...
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>>> for c in s: print(ord(c), end=" ")
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...
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97 172 4660 8364 32768
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Using escape sequences for code points greater than 127 is fine in small doses,
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@ -408,10 +414,10 @@ either the first or second line of the source file::
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#!/usr/bin/env python
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# -*- coding: latin-1 -*-
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u = u'abcdé'
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print ord(u[-1])
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print(ord(u[-1]))
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The syntax is inspired by Emacs's notation for specifying variables local to a
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file. Emacs supports many different variables, but Python only supports
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'coding'. The ``-*-`` symbols indicate that the comment is special; within
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@ -426,15 +432,15 @@ encoding declaration::
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#!/usr/bin/env python
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u = u'abcdé'
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print ord(u[-1])
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print(ord(u[-1]))
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When you run it with Python 2.4, it will output the following warning::
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amk:~$ python p263.py
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sys:1: DeprecationWarning: Non-ASCII character '\xe9'
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in file p263.py on line 2, but no encoding declared;
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sys:1: DeprecationWarning: Non-ASCII character '\xe9'
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in file p263.py on line 2, but no encoding declared;
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see http://www.python.org/peps/pep-0263.html for details
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Unicode Properties
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------------------
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@ -450,15 +456,15 @@ The following program displays some information about several characters, and
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prints the numeric value of one particular character::
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import unicodedata
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u = unichr(233) + unichr(0x0bf2) + unichr(3972) + unichr(6000) + unichr(13231)
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for i, c in enumerate(u):
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print i, '%04x' % ord(c), unicodedata.category(c),
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print unicodedata.name(c)
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print(i, '%04x' % ord(c), unicodedata.category(c), end=" ")
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print(unicodedata.name(c))
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# Get numeric value of second character
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print unicodedata.numeric(u[1])
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print(unicodedata.numeric(u[1]))
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When run, this prints::
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@ -545,7 +551,7 @@ Reading Unicode from a file is therefore simple::
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import codecs
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f = codecs.open('unicode.rst', encoding='utf-8')
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for line in f:
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print repr(line)
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print(repr(line))
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It's also possible to open files in update mode, allowing both reading and
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writing::
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@ -553,7 +559,7 @@ writing::
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f = codecs.open('test', encoding='utf-8', mode='w+')
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f.write(u'\u4500 blah blah blah\n')
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f.seek(0)
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print repr(f.readline()[:1])
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print(repr(f.readline()[:1]))
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f.close()
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Unicode character U+FEFF is used as a byte-order mark (BOM), and is often
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@ -606,8 +612,8 @@ default filesystem encoding is UTF-8, running the following program::
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f.close()
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import os
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print os.listdir('.')
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print os.listdir(u'.')
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print(os.listdir('.'))
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print(os.listdir(u'.'))
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will produce the following output::
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@ -619,7 +625,7 @@ The first list contains UTF-8-encoded filenames, and the second list contains
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the Unicode versions.
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Tips for Writing Unicode-aware Programs
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---------------------------------------
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@ -665,7 +671,7 @@ this code::
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unicode_name = filename.decode(encoding)
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f = open(unicode_name, 'r')
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# ... return contents of file ...
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However, if an attacker could specify the ``'base64'`` encoding, they could pass
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``'L2V0Yy9wYXNzd2Q='``, which is the base-64 encoded form of the string
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``'/etc/passwd'``, to read a system file. The above code looks for ``'/'``
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@ -701,7 +707,7 @@ Version 1.02: posted August 16 2005. Corrects factual errors.
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.. comment Describe obscure -U switch somewhere?
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.. comment Describe use of codecs.StreamRecoder and StreamReaderWriter
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.. comment
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.. comment
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Original outline:
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- [ ] Unicode introduction
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