使用逗号或点作为分隔符将 Python 字符串显式转换为浮点数

2022-01-09 00:00:00 python floating-point type-conversion localization

问题描述

如何明确告诉 python 使用点或逗号作为小数分隔符读取十进制数?我不知道将运行我的脚本的 PC 的本地化设置，这应该不会影响我的应用程序，我只想说:

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")

或

f = read_float_with_comma("3,14")

我认为写作

def read_float_with_comma(num):
    return float(num.replace(",", ".")

不安全，因为我不知道区域设置！

is not secure, because I don't know the locale settings!

解决方案

因为我不知道区域设置

because I don't know the locale settings

您可以使用 locale 模块进行查找一个>:

You could look that up using the locale module:

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

或

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

使用它，您的代码可以变成:

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)

更好的是，同一个模块为您提供了一个转换功能，称为 atof():

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)

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