How to format float with locale in Jinja2

Question

I have format floats like 1234567.89 in Jinja2 to the german format with separators 1.234.567,89

{{ '{:,.2f}'.format(value) }} produces 1,234,567.89

How can I change the seperators?

Answer 1

To format the number you can use the locale module, but not sure if you can do it straight in the Jinja template, I made a filter instead - I am usually creating filters for re-usability.

It's not clear how you are using Jinja; as standalone or as part of another application (Flask?). I am listing 2 methods/demos, 1 for standalone Jinja CLI, 1 for use in Flask.

Jinja template, just pass the value to the filter.

format_number_to_german.j2:

{{ value | format_to_german }}

For running jinja as CLI:

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import sys
from jinja2 import Environment, FileSystemLoader
import locale

##################################################################################################
def format_to_german(value):
    locale.setlocale(locale.LC_ALL, 'de_DE')
    return locale.format_string("%.2f", value, grouping=True)

##################################################################################################
def main():

    file_loader = FileSystemLoader('templates')
    env = Environment(loader=file_loader)
    env.filters["format_to_german"] = format_to_german

    value = 12345673113.8912

    template = env.get_template('format_number_to_german.j2')
    output = template.render(value=value)
    print(output)

# start:
if __name__ == '__main__':
    main()

Filter for Flask (in case you are using Jinja with Flask):

@filters.app_template_filter('format_to_german')
def format_to_german(value):
    import locale
    locale.setlocale(locale.LC_ALL, 'de_DE')
    return locale.format_string("%.2f", value, grouping=True)