使用Template格式化Python字符串的方法

class Template(metaclass=_TemplateMetaclass):
  """A string class for supporting $-substitutions."""

  delimiter = '$'
  idpattern = r'[_a-z][_a-z0-9]*'
  flags = _re.IGNORECASE

  def __init__(self, template):
    self.template = template

# 默认的定界符是$，即会将$之后内容匹配的字符串进行替换
s = Template('hello, $world!')
print(s.substitute(world='python'))
# hello, python!

# 可以通过继承Template类的方式进行替换
class CustomerTemplate(Template):
  delimiter = '*'

t = CustomerTemplate('hello, *world!')
print(t.substitute(world='python'))
# hello, python!