locale --- 國際化服務¶原始碼：Lib/locale.py
The locale module opens access to the POSIX locale database and
functionality. The POSIX locale mechanism allows programmers to deal with
certain cultural issues in an application, without requiring the programmer to
know all the specifics of each country where the software is executed.
The locale module is implemented on top of the _locale module,
which in turn uses an ANSI C locale implementation if available.
The locale module defines the following exception and functions:
Exception raised when the locale passed to setlocale() is not
recognized.
If locale is given and not None, setlocale() modifies the locale
setting for the category. The available categories are listed in the data
description below. locale may be a string, or an iterable of two strings
(language code and encoding). If it's an iterable, it's converted to a locale
name using the locale aliasing engine. An empty string specifies the user's
default settings. If the modification of the locale fails, the exception
Error is raised. If successful, the new locale setting is returned.
If locale is omitted or None, the current setting for category is
returned.
setlocale() is not thread-safe on most systems. Applications typically
start with a call of
import locale
locale.setlocale(locale.LC_ALL, '')
This sets the locale for all categories to the user's default setting (typically
specified in the LANG environment variable). If the locale is not
changed thereafter, using multithreading should not cause problems.
Returns the database of the local conventions as a dictionary. This dictionary has the following strings as keys:
分類 |
Key |
含義 |
|---|---|---|
|
Decimal point character. |
|
|
Sequence of numbers specifying
which relative positions the
|
|
|
Character used between groups. |
|
|
International currency symbol. |
|
|
Local currency symbol. |
|
|
Whether the currency symbol precedes the value (for positive resp. negative values). |
|
|
Whether the currency symbol is separated from the value by a space (for positive resp. negative values). |
|
|
Decimal point used for monetary values. |
|
|
Number of fractional digits used in local formatting of monetary values. |
|
|
Number of fractional digits used in international formatting of monetary values. |
|
|
Group separator used for monetary values. |
|
|
Equivalent to |
|
|
Symbol used to annotate a positive monetary value. |
|
|
Symbol used to annotate a negative monetary value. |
|
|
The position of the sign (for positive resp. negative values), see below. |
All numeric values can be set to CHAR_MAX to indicate that there is no
value specified in this locale.
The possible values for 'p_sign_posn' and 'n_sign_posn' are given below.
Value |
Explanation |
|---|---|
|
Currency and value are surrounded by parentheses. |
|
The sign should precede the value and currency symbol. |
|
The sign should follow the value and currency symbol. |
|
The sign should immediately precede the value. |
|
The sign should immediately follow the value. |
|
Nothing is specified in this locale. |
The function temporarily sets the LC_CTYPE locale to the LC_NUMERIC
locale or the LC_MONETARY locale if locales are different and numeric or
monetary strings are non-ASCII. This temporary change affects other threads.
在 3.7 版的變更: The function now temporarily sets the LC_CTYPE locale to the
LC_NUMERIC locale in some cases.
Return some locale-specific information as a string. This function is not available on all systems, and the set of possible options might also vary across platforms. The possible argument values are numbers, for which symbolic constants are available in the locale module.
The nl_langinfo() function accepts one of the following keys. Most
descriptions are taken from the corresponding description in the GNU C
library.
Get a string with the name of the character encoding used in the selected locale.
Get a string that can be used as a format string for time.strftime() to
represent date and time in a locale-specific way.
Get a string that can be used as a format string for time.strftime() to
represent a date in a locale-specific way.
Get a string that can be used as a format string for time.strftime() to
represent a time in a locale-specific way.
Get a format string for time.strftime() to represent time in the am/pm
format.
Get the name of the n-th day of the week.
備註
This follows the US convention of DAY_1 being Sunday, not the
international convention (ISO 8601) that Monday is the first day of the
week.
Get the abbreviated name of the n-th day of the week.
Get the name of the n-th month.
Get the abbreviated name of the n-th month.
Get the radix character (decimal dot, decimal comma, etc.).
Get the separator character for thousands (groups of three digits).
Get a regular expression that can be used with the regex function to recognize a positive response to a yes/no question.
Get a regular expression that can be used with the regex(3) function to
recognize a negative response to a yes/no question.
Get the currency symbol, preceded by "-" if the symbol should appear before the value, "+" if the symbol should appear after the value, or "." if the symbol should replace the radix character.
Get a string which describes how years are counted and displayed for each era in a locale.
Most locales do not define this value. An example of a locale which does define this value is the Japanese one. In Japan, the traditional representation of dates includes the name of the era corresponding to the then-emperor's reign.
Normally it should not be necessary to use this value directly. Specifying
the E modifier in their format strings causes the time.strftime()
function to use this information.
The format of the returned string is specified in The Open Group Base
Specifications Issue 8, paragraph 7.3.5.2 LC_TIME C-Language Access.
Get a format string for time.strftime() to represent date and time in a
locale-specific era-based way.
Get a format string for time.strftime() to represent a date in a
locale-specific era-based way.
Get a format string for time.strftime() to represent a time in a
locale-specific era-based way.
Get a string consisting of up to 100 semicolon-separated symbols used to represent the values 0 to 99 in a locale-specific way. In most locales this is an empty string.
Tries to determine the default locale settings and returns them as a tuple of
the form (language code, encoding).
According to POSIX, a program which has not called setlocale(LC_ALL, '')
runs using the portable 'C' locale. Calling setlocale(LC_ALL, '') lets
it use the default locale as defined by the LANG variable. Since we
do not want to interfere with the current locale setting we thus emulate the
behavior in the way described above.
To maintain compatibility with other platforms, not only the LANG
variable is tested, but a list of variables given as envvars parameter. The
first found to be defined will be used. envvars defaults to the search
path used in GNU gettext; it must always contain the variable name
'LANG'. The GNU gettext search path contains 'LC_ALL',
'LC_CTYPE', 'LANG' and 'LANGUAGE', in that order.
Except for the code 'C', the language code corresponds to RFC 1766.
language code and encoding may be None if their values cannot be
determined.
Deprecated since version 3.11, will be removed in version 3.15.
Returns the current setting for the given locale category as sequence containing
language code, encoding. category may be one of the LC_* values
except LC_ALL. It defaults to LC_CTYPE.
Except for the code 'C', the language code corresponds to RFC 1766.
language code and encoding may be None if their values cannot be
determined.
Return the locale encoding used for text data, according to user preferences. User preferences are expressed differently on different systems, and might not be available programmatically on some systems, so this function only returns a guess.
On some systems, it is necessary to invoke setlocale() to obtain the
user preferences, so this function is not thread-safe. If invoking setlocale
is not necessary or desired, do_setlocale should be set to False.
On Android or if the Python UTF-8 Mode is enabled, always
return 'utf-8', the locale encoding and the do_setlocale
argument are ignored.
The Python preinitialization configures the LC_CTYPE locale. See also the filesystem encoding and error handler.
在 3.7 版的變更: The function now always returns "utf-8" on Android or if the
Python UTF-8 Mode is enabled.
Get the current locale encoding:
On Android and VxWorks, return "utf-8".
On Unix, return the encoding of the current LC_CTYPE locale.
Return "utf-8" if nl_langinfo(CODESET) returns an empty string:
for example, if the current LC_CTYPE locale is not supported.
On Windows, return the ANSI code page.
The Python preinitialization configures the LC_CTYPE locale. See also the filesystem encoding and error handler.
This function is similar to
getpreferredencoding(False) except this
function ignores the Python UTF-8 Mode.
在 3.11 版被加入.
Returns a normalized locale code for the given locale name. The returned locale
code is formatted for use with setlocale(). If normalization fails, the
original name is returned unchanged.
If the given encoding is not known, the function defaults to the default
encoding for the locale code just like setlocale().
Compares two strings according to the current LC_COLLATE setting. As
any other compare function, returns a negative, or a positive value, or 0,
depending on whether string1 collates before or after string2 or is equal to
it.
Transforms a string to one that can be used in locale-aware
comparisons. For example, strxfrm(s1) < strxfrm(s2) is
equivalent to strcoll(s1, s2) < 0. This function can be used
when the same string is compared repeatedly, e.g. when collating a
sequence of strings.
Formats a number val according to the current LC_NUMERIC setting.
The format follows the conventions of the % operator. For floating-point
values, the decimal point is modified if appropriate. If grouping is True,
also takes the grouping into account.
If monetary is true, the conversion uses monetary thousands separator and grouping strings.
Processes formatting specifiers as in format % val, but takes the current
locale settings into account.
在 3.7 版的變更: The monetary keyword parameter was added.
Formats a number val according to the current LC_MONETARY settings.
The returned string includes the currency symbol if symbol is true, which is
the default. If grouping is True (which is not the default), grouping is done
with the value. If international is True (which is not the default), the
international currency symbol is used.
備註
This function will not work with the 'C' locale, so you have to set a
locale via setlocale() first.
Formats a floating-point number using the same format as the built-in function
str(float), but takes the decimal point into account.
Converts a string into a normalized number string, following the
LC_NUMERIC settings.
在 3.5 版被加入.
Converts a normalized number string into a formatted string following the
LC_NUMERIC settings.
在 3.10 版被加入.
Converts a string to a number, following the LC_NUMERIC settings,
by calling func on the result of calling delocalize() on string.
Converts a string to an integer, following the LC_NUMERIC conventions.
Locale category for the character type functions. Most importantly, this
category defines the text encoding, i.e. how bytes are interpreted as
Unicode codepoints. See PEP 538 and PEP 540 for how this variable
might be automatically coerced to C.UTF-8 to avoid issues created by
invalid settings in containers or incompatible settings passed over remote
SSH connections.
Python doesn't internally use locale-dependent character transformation functions
from ctype.h. Instead, an internal pyctype.h provides locale-independent
equivalents like Py_TOLOWER.
Locale category for sorting strings. The functions strcoll() and
strxfrm() of the locale module are affected.
Locale category for the formatting of time. The function time.strftime()
follows these conventions.
Locale category for formatting of monetary values. The available options are
available from the localeconv() function.
Locale category for message display. Python currently does not support
application specific locale-aware messages. Messages displayed by the operating
system, like those returned by os.strerror() might be affected by this
category.
This value may not be available on operating systems not conforming to the POSIX standard, most notably Windows.
Locale category for formatting numbers. The functions format_string(),
atoi(), atof() and str() of the locale module are
affected by that category. All other numeric formatting operations are not
affected.
Combination of all locale settings. If this flag is used when the locale is changed, setting the locale for all categories is attempted. If that fails for any category, no category is changed at all. When the locale is retrieved using this flag, a string indicating the setting for all categories is returned. This string can be later used to restore the settings.
This is a symbolic constant used for different values returned by
localeconv().
範例：
>>> import locale
>>> loc = locale.getlocale() # get current locale
# use German locale; name might vary with platform
>>> locale.setlocale(locale.LC_ALL, 'de_DE')
>>> locale.strcoll('f\xe4n', 'foo') # compare a string containing an umlaut
>>> locale.setlocale(locale.LC_ALL, '') # use user's preferred locale
>>> locale.setlocale(locale.LC_ALL, 'C') # use default (C) locale
>>> locale.setlocale(locale.LC_ALL, loc) # restore saved locale
The C standard defines the locale as a program-wide property that may be relatively expensive to change. On top of that, some implementations are broken in such a way that frequent locale changes may cause core dumps. This makes the locale somewhat painful to use correctly.
Initially, when a program is started, the locale is the C locale, no matter
what the user's preferred locale is. There is one exception: the
LC_CTYPE category is changed at startup to set the current locale
encoding to the user's preferred locale encoding. The program must explicitly
say that it wants the user's preferred locale settings for other categories by
calling setlocale(LC_ALL, '').
It is generally a bad idea to call setlocale() in some library routine,
since as a side effect it affects the entire program. Saving and restoring it
is almost as bad: it is expensive and affects other threads that happen to run
before the settings have been restored.
If, when coding a module for general use, you need a locale independent version
of an operation that is affected by the locale (such as
certain formats used with time.strftime()), you will have to find a way to
do it without using the standard library routine. Even better is convincing
yourself that using locale settings is okay. Only as a last resort should you
document that your module is not compatible with non-C locale settings.
The only way to perform numeric operations according to the locale is to use the
special functions defined by this module: atof(), atoi(),
format_string(), str().
There is no way to perform case conversions and character classifications according to the locale. For (Unicode) text strings these are done according to the character value only, while for byte strings, the conversions and classifications are done according to the ASCII value of the byte, and bytes whose high bit is set (i.e., non-ASCII bytes) are never converted or considered part of a character class such as letter or whitespace.
Extension modules should never call setlocale(), except to find out what
the current locale is. But since the return value can only be used portably to
restore it, that is not very useful (except perhaps to find out whether or not
the locale is C).
When Python code uses the locale module to change the locale, this also
affects the embedding application. If the embedding application doesn't want
this to happen, it should remove the _locale extension module (which does
all the work) from the table of built-in modules in the config.c file,
and make sure that the _locale module is not accessible as a shared
library.
The locale module exposes the C library's gettext interface on systems that
provide this interface. It consists of the functions gettext(),
dgettext(), dcgettext(), textdomain(), bindtextdomain(),
and bind_textdomain_codeset(). These are similar to the same functions in
the gettext module, but use the C library's binary format for message
catalogs, and the C library's search algorithms for locating message catalogs.
Python applications should normally find no need to invoke these functions, and
should use gettext instead. A known exception to this rule are
applications that link with additional C libraries which internally invoke
C functions gettext or dcgettext. For these applications, it may be
necessary to bind the text domain, so that the libraries can properly locate
their message catalogs.