22.2. locale — Internationalization services

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 locale.Error

Exception raised when setlocale() fails.

locale.setlocale(category[, locale])

If locale is specified, it may be a string, a tuple of the form (language code, encoding), or None. If it is a tuple, it is converted to a string using the locale aliasing engine. 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. The value is the name of a locale. 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.

Changed in version 2.0:

Changed in version 2.0: Added support for tuple values of the locale parameter.

locale.localeconv()

Returns the database of the local conventions as a dictionary. This dictionary has the following strings as keys:

Category	Key	Meaning
LC_NUMERIC	'decimal_point'	Decimal point character.
	'grouping'	Sequence of numbers specifying which relative positions the 'thousands_sep' is expected. If the sequence is terminated with CHAR_MAX, no further grouping is performed. If the sequence terminates with a 0, the last group size is repeatedly used.
	'thousands_sep'	Character used between groups.
LC_MONETARY	'int_curr_symbol'	International currency symbol.
	'currency_symbol'	Local currency symbol.
	'p_cs_precedes/n_cs_precedes'	Whether the currency symbol precedes the value (for positive resp. negative values).
	'p_sep_by_space/n_sep_by_space'	Whether the currency symbol is separated from the value by a space (for positive resp. negative values).
	'mon_decimal_point'	Decimal point used for monetary values.
	'frac_digits'	Number of fractional digits used in local formatting of monetary values.
	'int_frac_digits'	Number of fractional digits used in international formatting of monetary values.
	'mon_thousands_sep'	Group separator used for monetary values.
	'mon_grouping'	Equivalent to 'grouping', used for monetary values.
	'positive_sign'	Symbol used to annotate a positive monetary value.
	'negative_sign'	Symbol used to annotate a negative monetary value.
	'p_sign_posn/n_sign_posn'	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
0	Currency and value are surrounded by parentheses.
1	The sign should precede the value and currency symbol.
2	The sign should follow the value and currency symbol.
3	The sign should immediately precede the value.
4	The sign should immediately follow the value.
CHAR_MAX	Nothing is specified in this locale.

locale.nl_langinfo(option)

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.

locale.CODESET

Get a string with the name of the character encoding used in the selected locale.

locale.D_T_FMT

Get a string that can be used as a format string for strftime() to represent time and date in a locale-specific way.

locale.D_FMT

Get a string that can be used as a format string for strftime() to represent a date in a locale-specific way.

locale.T_FMT

Get a string that can be used as a format string for strftime() to represent a time in a locale-specific way.

locale.T_FMT_AMPM

Get a format string for strftime() to represent time in the am/pm format.

DAY_1 ... DAY_7

Get the name of the n-th day of the week.

Note

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.

ABDAY_1 ... ABDAY_7

Get the abbreviated name of the n-th day of the week.

MON_1 ... MON_12

Get the name of the n-th month.

ABMON_1 ... ABMON_12

Get the abbreviated name of the n-th month.

locale.RADIXCHAR

Get the radix character (decimal dot, decimal comma, etc.)

locale.THOUSEP

Get the separator character for thousands (groups of three digits).

locale.YESEXPR

Get a regular expression that can be used with the regex function to recognize a positive response to a yes/no question.

Note

The expression is in the syntax suitable for the :cfunc:`regex` function from the C library, which might differ from the syntax used in re.

locale.NOEXPR

Get a regular expression that can be used with the regex(3) function to recognize a negative response to a yes/no question.

locale.CRNCYSTR

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.

locale.ERA

Get a string that represents the era used in the current 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 strftime() function to use this information. The format of the returned string is not specified, and therefore you should not assume knowledge of it on different systems.

locale.ERA_D_T_FMT

Get a format string for strftime() to represent dates and times in a locale-specific era-based way.

locale.ERA_D_FMT

Get a format string for strftime() to represent time in a locale-specific era-based way.

locale.ALT_DIGITS

Get a representation of up to 100 values used to represent the values 0 to 99.

locale.getdefaultlocale([envvars])

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 'LANGUAGE', 'LC_ALL', 'LC_CTYPE', and 'LANG', 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.

New in version 2.0:

New in version 2.0.