Convert Python strings into floats explicitly using the comma or the point as separators

floating-point, localization, python, type-conversion

Solution

because I don't know the locale settings

You could look that up using the `locale` module:

>>> locale.nl_langinfo(locale.RADIXCHAR)
'.'

or

>>> locale.localeconv()['decimal_point']
'.'

Using that, your code could become:

import locale
_locale_radix = locale.localeconv()['decimal_point']

def read_float_with_comma(num):
    if _locale_radix != '.':
        num = num.replace(_locale_radix, ".")
    return float(num)

Better still, the same module has a conversion function for you, called `atof()`:

import locale

def read_float_with_comma(num):
    return locale.atof(num)

Problem

How can I explicitly tell python to read a decimal number using the point or the comma as a decimal separator? I don't know the localization settings of the PC that will run my script, and this should not influence my application, I only want to say: ``` f = read_float_with_point("3.14") ``` or ``` f = read_float_with_comma("3,14") ``` I think that writing ``` def read_float_with_comma(num): return float(num.replace(",", ".") ``` is not secure, because I don't know the locale settings!

Original source