Split Every N Character

Bank Card

def bank_card(self, message, n=4, fill=' ', strip=False):
    """
    Format bank card, split every n character, n default 4.
    :param message:
    :param n:
    :param fill:
    :param strip:
    :return:
    """
    return fill.join(re.findall(r'.{1,%s}' % (n, ), re.sub(r'\s+', '', message) if strip else message))

• Usage

  In [2]: bank_card('6225xxxxxxxxxxxx')
  Out[2]: '6225 xxxx xxxx xxxx'
  
  In [3]: bank_card('6225xxxxxxxxxxxxxxx')
  Out[3]: '6225 xxxx xxxx xxxx xxx'
  

References

[1] Brandon L Burnett@StackOverflow, Split python string every nth character?