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.. -*- mode: rst; encoding: utf-8 -*-
.. _numbers:
=================
Number Formatting
=================
Support for locale-specific formatting and parsing of numbers is provided by
the ``babel.numbers`` module:
.. code-block:: pycon
>>> from babel.numbers import format_number, format_decimal, format_percent
Examples:
.. code-block:: pycon
>>> format_decimal(1.2345, locale='en_US')
u'1.234'
>>> format_decimal(1.2345, locale='sv_SE')
u'1,234'
>>> format_decimal(12345, locale='de_DE')
u'12.345'
Pattern Syntax
==============
While Babel makes it simple to use the appropriate number format for a given
locale, you can also force it to use custom patterns. As with date/time
formatting patterns, the patterns Babel supports for number formatting are
based on the `Locale Data Markup Language specification`_ (LDML).
Examples:
.. code-block:: pycon
>>> format_decimal(-1.2345, format='#,##0.##;-#', locale='en')
u'-1.23'
>>> format_decimal(-1.2345, format='#,##0.##;(#)', locale='en')
u'(1.23)'
The syntax for custom number format patterns is described in detail in the
the specification. The following table is just a relatively brief overview.
.. _`Locale Data Markup Language specification`: http://unicode.org/reports/tr35/#Number_Format_Patterns
+----------+-----------------------------------------------------------------+
| Symbol | Description |
+==========+=================================================================+
| ``0`` | Digit |
+----------+-----------------------------------------------------------------+
| ``1-9`` | '1' through '9' indicate rounding. |
+----------+-----------------------------------------------------------------+
| ``@`` | Significant digit |
+----------+-----------------------------------------------------------------+
| ``#`` | Digit, zero shows as absent |
+----------+-----------------------------------------------------------------+
| ``.`` | Decimal separator or monetary decimal separator |
+----------+-----------------------------------------------------------------+
| ``-`` | Minus sign |
+----------+-----------------------------------------------------------------+
| ``,`` | Grouping separator |
+----------+-----------------------------------------------------------------+
| ``E`` | Separates mantissa and exponent in scientific notation |
+----------+-----------------------------------------------------------------+
| ``+`` | Prefix positive exponents with localized plus sign |
+----------+-----------------------------------------------------------------+
| ``;`` | Separates positive and negative subpatterns |
+----------+-----------------------------------------------------------------+
| ``%`` | Multiply by 100 and show as percentage |
+----------+-----------------------------------------------------------------+
| ``‰`` | Multiply by 1000 and show as per mille |
+----------+-----------------------------------------------------------------+
| ``¤`` | Currency sign, replaced by currency symbol. If doubled, |
| | replaced by international currency symbol. If tripled, uses the |
| | long form of the decimal symbol. |
+----------+-----------------------------------------------------------------+
| ``'`` | Used to quote special characters in a prefix or suffix |
+----------+-----------------------------------------------------------------+
| ``*`` | Pad escape, precedes pad character |
+----------+-----------------------------------------------------------------+
Parsing Numbers
===============
Babel can also parse numeric data in a locale-sensitive manner:
.. code-block:: pycon
>>> from babel.numbers import parse_decimal, parse_number
Examples:
.. code-block:: pycon
>>> parse_decimal('1,099.98', locale='en_US')
1099.98
>>> parse_decimal('1.099,98', locale='de')
1099.98
>>> parse_decimal('2,109,998', locale='de')
Traceback (most recent call last):
...
NumberFormatError: '2,109,998' is not a valid decimal number
.. note:: Number parsing is not properly implemented yet
|
