使用正则表达式逗号分隔南亚编号系统中的大量数字 [英] Using regular expression to comma separate a large number in south asian numbering system

问题描述

我正在尝试根据南亚数字编号系统找到一个正则表达式以逗号分隔大量数字。

一些示例：

• 1,000,000 （阿拉伯语）为 10,00,000 （印度/印度/南亚）


• 1,000,000,000 （阿拉伯语）为 100,00,00,000 （印度/ H / SA）。

• 1,000,000 (Arabic) is 10,00,000 (Indian/Hindu/South Asian)
• 1,000,000,000 (Arabic) is 100,00,00,000 (Indian/H/SA).

逗号模式每7位重复一次。例如，
1,00,00,000,00,00,000 。

The comma pattern repeats for every 7 digits. For example, 1,00,00,000,00,00,000.

来自Mastering Regular书Friedl的表达式，对于阿拉伯数字系统，我有以下正则表达式：

From the book Mastering Regular Expressions by Friedl , I have the following regular expression for Arabic numbering system:

r'(?<=\d)(?=(\d{3})+(?!\d))'

对于印度编号系统，我想出了以下表达式，但不适用于8位以上的数字：

For Indian numbering system, I have come up with the following expression but it doesn't work for numbers with more than 8 digits:

r'(?<=\d)(?=(((\d{2}){0,2}\d{3})(?=\b)))'

使用上述模式，我得到 100000000,00,00,000 。

Using the above pattern, I get 100000000,00,00,000.

我正在使用Python re 模块（ re.sub（））。有什么想法吗？

I am using the Python re module (re.sub()). Any ideas?

推荐答案

尝试一下：

(?<=\d)(?=(\d{2}){0,2}\d{3}(\d{7})*(?!\d))

例如：

>>> import re
>>> inp = ["1" + "0"*i for i in range(20)]
>>> [re.sub(r"(?<=\d)(?=(\d{2}){0,2}\d{3}(\d{7})*(?!\d))", ",", i) 
     for i in inp]
['1', '10', '100', '1,000', '10,000', '1,00,000', '10,00,000', '1,00,00,000', 
 '10,00,00,000', '100,00,00,000', '1,000,00,00,000', '10,000,00,00,000', 
 '1,00,000,00,00,000', '10,00,000,00,00,000', '1,00,00,000,00,00,000', 
 '10,00,00,000,00,00,000', '100,00,00,000,00,00,000', 
 '1,000,00,00,000,00,00,000', '10,000,00,00,000,00,00,000',
 '1,00,000,00,00,000,00,00,000']

作为正则表达式：

result = re.sub(
    r"""(?x)       # Enable verbose mode (comments)
    (?<=\d)        # Assert that we're not at the start of the number.
    (?=            # Assert that it's possible to match:
     (\d{2}){0,2}  # 0, 2 or 4 digits,
     \d{3}         # followed by 3 digits,
     (\d{7})*      # followed by 0, 7, 14, 21 ... digits,
     (?!\d)        # and no more digits after that.
    )              # End of lookahead assertion.""", 
    ",", subject)

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