date_dic = {
'ymd': '{0.year}:{0.month}:{0.day}',
'dmy': '{0.day}/{0.month}/{0.year}',
'mdy': '{0.month}-{0.day}-{0.year}',
}
class Date:
def __init__(self, year, month, day):
self.year = year
self.month = month
self.day = day
def __format__(self, format_spec):
# 默认打印ymd的{0.year}:{0.month}:{0.day}格式
if not format_spec or format_spec not in date_dic:
format_spec = 'ymd'
fmt = date_dic[format_spec]
return fmt.format(self)
d1 = Date(2016, 12, 29)
print(format(d1))
2016:12:29
print('{:mdy}'.format(d1))
12-29-2016
