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:
| category[, locale]) | 
(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: Added support for tuple values of the locale parameter.
| ) | 
| 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 a0, 
             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. | 
| 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.
| [envvars]) | 
(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.
| [category]) | 
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.
| [do_setlocale]) | 
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.
New in version 2.3.
| localename) | 
If the given encoding is not known, the function defaults to the default encoding for the locale code just like setlocale(). New in version 2.0.
| [category]) | 
The default setting is determined by calling getdefaultlocale(). category defaults to LC_ALL. New in version 2.0.
| string1, string2) | 
0, depending on
  whether string1 collates before or after string2 or is
  equal to it.
| string) | 
| format, val[, grouping[, monetary]]) | 
% 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.
Please note that this function will only work for exactly one %char specifier. For whole format strings, use format_string().
Changed in version 2.5: Added the monetary parameter.
| format, val[, grouping]) | 
format % val,
  but takes the current locale settings into account.
New in version 2.5.
| val[, symbol[, grouping[, international]]]) | 
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.
Note that this function will not work with the `C' locale, so you have to set a locale via setlocale() first.
New in version 2.5.
| float) | 
str(float), but takes the decimal
  point into account.
| string) | 
| string) | 
The nl_langinfo function accepts one of the following keys. Most descriptions are taken from the corresponding description in the GNU C library.
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.
Example:
>>> import locale
>>> loc = locale.getlocale(locale.LC_ALL) # get current locale
>>> locale.setlocale(locale.LC_ALL, 'de_DE') # use German locale; name might vary with platform
>>> 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