Edgewall Software
Last modified 8 years ago Last modified on 06/19/07 19:22:48

Number Formatting

Support for locale-specific formatting and parsing of numbers is provided by the babel.numbers module:

>>> from babel.numbers import format_number, format_decimal, format_percent

Examples:

>>> 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'

1   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:

>>> 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.

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

2   Parsing Numbers

Babel can also parse numeric data in a locale-sensitive manner:

>>> from babel.numbers import parse_decimal, parse_number

Examples:

>>> 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


See also: User Guide, Documentation