使用正则表达式逗号分隔南亚编号系统中的大量数字

Question

我正在尝试找到一个基于南亚编号系统的正则表达式，以逗号分隔大量数字。

一些例子：

• 1,000,000（阿拉伯文）是10,00,000（印度/印度/南亚）
• 1,000,000,000（阿拉伯文）是100,00,00,000（印度文/ H / SA）。

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

从Friedl撰写的Mastering Regular Expressions一书中，我有以下阿拉伯数字系统的正则表达式：

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

对于印度编号系统，我想出了以下表达式，但不适用于超过8位数字的数字：

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

使用上述模式，我得到100000000,00,00,000。

我正在使用Pythonre模块（re.sub()）。有任何想法吗？

Answer 1

尝试这个：

(?<=\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']

作为评论正则表达式：

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)