python f-string format float comma

How to format a float with a comma as decimal separator in an f-string?

stackoverflow.com › questions › 55379722 › how-to-format-a-float-with-a-comma-as-decimal-separator-in-an-f-string

If you want to format floats with a comma within the f-string, you can either use replace after casting the float to a string:

position = 123.456
f"Position\t{str(position).replace('.',',')}"

A second option is to use the Python standard library module locale (but it is not thread-safe):

import locale
locale.setlocale(locale.LC_ALL, 'nl_NL')
f"Position\t{locale.format('%.3f', position)}"

A third option is to use the library babel (preferred in case of library routines):

from babel.numbers import format_decimal
f"Position\t{format_decimal(position, locale='nl_NL')}"

All three options return the same result for the given example:

'Position\t123,456'

Answer from kadee on Stack Overflow

Stack Overflow

stackoverflow.com › questions › 55379722 › how-to-format-a-float-with-a-comma-as-decimal-separator-in-an-f-string

python - How to format a float with a comma as decimal separator in an f-string? - Stack Overflow

Top answer

1 of 6

If you want to format floats with a comma within the f-string, you can either use replace after casting the float to a string:

position = 123.456
f"Position\t{str(position).replace('.',',')}"

A second option is to use the Python standard library module locale (but it is not thread-safe):

import locale
locale.setlocale(locale.LC_ALL, 'nl_NL')
f"Position\t{locale.format('%.3f', position)}"

A third option is to use the library babel (preferred in case of library routines):

from babel.numbers import format_decimal
f"Position\t{format_decimal(position, locale='nl_NL')}"

All three options return the same result for the given example:

'Position\t123,456'

2 of 6

As @michel-de-ruiter mentioned, the f format does not work with locale. On the other hand, you can't set the precision using n format. For example, if you want 4 digits after decimal separator:

import locale
locale.setlocale(locale.LC_ALL, 'nl_NL')

position = 123.45678999
print(f'{position:.4n}')  # output: 123,4 (not quite what we wanted!)

However, you can round the number with the desired precision before formatting it:

print(f'{round(position, 4):n}')  # output: 123,4567 (that's it!)

Real Python

realpython.com › how-to-python-f-string-format-float

How to Format Floats Within F-Strings in Python – Real Python

April 24, 2024 - To use Python’s format specifiers in a replacement field, you separate them from the expression with a colon (:). As you can see, your float has been rounded to two decimal places. You achieved this by adding the format specifier .2f into the replacement field. The 2 is the precision, while the lowercase f is an example of a presentation type. You’ll see more of these later. Note: When you use a format specifier, you don’t actually change the underlying number. You only improve its display. Python’s f-strings also have their own mini-language that allows you to format your output in a variety of different ways.

Discussions

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f-string - converting float to string with set decimals and thousand separator

import locale a = 1100300.506 locale.setlocale(locale.LC_ALL, 'no_NO') locale._override_localeconv = {'thousands_sep': ' ','decimal_point': '.'} print(locale.format_string('%.2f', a, grouping=True)) More on reddit.com

r/learnpython

December 8, 2021

How to use python with comma (,) instead of dot (.) as decimal separator?

You convert it before printing.

>>> print(str(3.5).replace(".",","))
3,5

Above code converts 3.5 to string, then replaces dot with comma.

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