Django’s formatting system is capable of displaying dates, times and numbers in templates using the format specified for the current locale. It also handles localized input in forms.
When it’s enabled, two users accessing the same content may see dates, times and numbers formatted in different ways, depending on the formats for their current locale.
The formatting system is disabled by default. To enable it, it’s
necessary to set USE_L10N = True in your settings file.
Note
The default settings.py file created by django-admin
startproject includes USE_L10N = True
for convenience. Note, however, that to enable number formatting with
thousand separators it is necessary to set USE_THOUSAND_SEPARATOR
= True in your settings file. Alternatively, you
could use intcomma to format numbers in your template.
Note
There is also an independent but related USE_I18N setting that
controls if Django should activate translation. See
Translation for more details.
When formatting is enabled, Django can use localized formats when parsing dates, times and numbers in forms. That means it tries different formats for different locales when guessing the format used by the user when inputting data on forms.
Note
Django uses different formats for displaying data to those it uses for
parsing data. Most notably, the formats for parsing dates can’t use the
%a (abbreviated weekday name), %A (full weekday name),
%b (abbreviated month name), %B (full month name),
or %p (AM/PM).
To enable a form field to localize input and output data simply use its
localize argument:
class CashRegisterForm(forms.Form):
product = forms.CharField()
revenue = forms.DecimalField(max_digits=4, decimal_places=2, localize=True)
When you have enabled formatting with USE_L10N, Django
will try to use a locale specific format whenever it outputs a value
in a template.
However, it may not always be appropriate to use localized values – for example, if you’re outputting JavaScript or XML that is designed to be machine-readable, you will always want unlocalized values. You may also want to use localization in selected templates, rather than using localization everywhere.
To allow for fine control over the use of localization, Django
provides the l10n template library that contains the following
tags and filters.
localize¶Enables or disables localization of template variables in the contained block.
This tag allows a more fine grained control of localization than
USE_L10N.
To activate or deactivate localization for a template block, use:
{% load l10n %}
{% localize on %}
{{ value }}
{% endlocalize %}
{% localize off %}
{{ value }}
{% endlocalize %}
Note
The value of USE_L10N isn’t respected inside of a
{% localize %} block.
See localize and unlocalize for template filters that will
do the same job on a per-variable basis.
localize¶Forces localization of a single value.
For example:
{% load l10n %}
{{ value|localize }}
To disable localization on a single value, use unlocalize. To control
localization over a large section of a template, use the localize template
tag.
Django provides format definitions for many locales, but sometimes you might want to create your own, because a format files doesn’t exist for your locale, or because you want to overwrite some of the values.
To use custom formats, specify the path where you’ll place format files
first. To do that, just set your FORMAT_MODULE_PATH setting to
the package where format files will exist, for instance:
FORMAT_MODULE_PATH = [
'mysite.formats',
'some_app.formats',
]
Files are not placed directly in this directory, but in a directory named as
the locale, and must be named formats.py. Be careful not to put sensitive
information in these files as values inside can be exposed if you pass the
string to django.utils.formats.get_format() (used by the date
template filter).
To customize the English formats, a structure like this would be needed:
mysite/
formats/
__init__.py
en/
__init__.py
formats.py
where formats.py contains custom format definitions. For example:
THOUSAND_SEPARATOR = '\xa0'
to use a non-breaking space (Unicode 00A0) as a thousand separator,
instead of the default for English, a comma.
Some locales use context-sensitive formats for numbers, which Django’s localization system cannot handle automatically.
The Swiss number formatting depends on the type of number that is being formatted. For monetary values, a comma is used as the thousand separator and a decimal point for the decimal separator. For all other numbers, a comma is used as decimal separator and a space as thousand separator. The locale format provided by Django uses the generic separators, a comma for decimal and a space for thousand separators.
Oct 31, 2018