По чертям, я сделал довольно всеобъемлющую объектно-ориентированную переписку:
import datetime
class Date(object):
def __init__(self, s):
if isinstance(s, Date):
self.date = s.date
elif isinstance(s, datetime.date):
self.date = s
else:
self.date = datetime.datetime.strptime(s, "%d/%m/%Y")
def __add__(self, val):
if isinstance(val, Life):
val = val.life
elif not isinstance(val, datetime.timedelta):
val = datetime.timedelta(val)
return self.__class__(self.date + val)
def __cmp__(self, val):
return (self.date - val.date).days
def __str__(self):
return self.date.strftime("%d/%m/%Y")
class Life(object):
def __init__(self, s):
if isinstance(s, Life):
self.life = s.life
elif isinstance(s, datetime.timedelta):
self.life = s
else:
self.life = datetime.timedelta(days=int(s))
def __str__(self):
return str(self.life.days)
class Product(object):
FMT = "{0:10} {1:10} {2:24}".format
def __init__(self, date, life, name):
super(Product,self).__init__()
self.date = Date(date)
self.life = Life(life)
self.name = str(name).strip()
def __str__(self):
return Product.FMT(self.date, self.life, self.name)
def expires(self):
return Date(self.date + self.life)
@classmethod
def get(cls):
date = getClass(Date, "Please enter the date (DD/MM/YYYY): ")
life = getClass(Life, "Please enter the life (in days): ")
name = raw_input("Please enter the name of the cheese: ")
return cls(date, life, name)
def vals(self):
return self.date, self.life, self.name
class FileOf(object):
def __init__(self, cls):
self.data = {}
self.cls = cls
def loadFile(self, fname, mode='r', sep=':'):
_data = self.data
_cls = self.cls
with open(fname, mode) as inf:
for line in inf:
try:
items = line.strip().split(sep)
id = items.pop(0)
_data[id] = _cls(*items)
except ValueError, e:
print(e)
return self
def saveFile(self, fname, mode='w', sep=':', eol='\n', key=None):
_data = self.data
keys = _data.keys()
keys.sort(key=key)
with open(fname, mode) as outf:
for id in keys:
outf.write(str(id)+sep)
outf.write(sep.join(str(v) for v in _data[id].vals()))
outf.write(eol)
return self
def addNew(self):
id = getNewKey(self.data, "Please enter the new ID: ")
obj = getClass(self.cls)
self.data[id] = obj
return self
def printAll(self, key=None):
_data = self.data
_cls = self.cls
ID = "{0:4} ".format
print ID("id") + _cls.FMT("Date", "Life", "Name")
keys = _data.keys()
keys.sort(key=key)
for id in keys:
print ID(id) + _cls.FMT(*(_data[id].vals()))
return self
def filter(self, filterFn):
newFile = FileOf(self.cls)
newFile.data = {id:item for id,item in self.data.iteritems() if filterFn(id, item)}
return newFile
def getNewKey(keys, msg='', keytype=str):
"Prompt for a key not already in keys"
while True:
key = keytype(raw_input(msg))
if key in keys:
print("This key already exists. Please try again.")
else:
return key
def getClass(cls, *args, **kwargs):
"Return a new instance of given class; prompt for required values"
if hasattr(cls, 'get'):
# if the class knows how to 'get' itself, let it
return cls.get(*args, **kwargs)
else:
# otherwise we assume the class knows how to init itself from a string
while True:
s = raw_input(*args)
try:
return cls(s, **kwargs)
except ValueError, e:
print(e)
def getExpired(cheeses, asOf=None):
asOf = Date(asOf) if asOf else getClass(Date, "Please enter expiration test date (DD/MM/YYYY): ")
return cheeses.filter(lambda id,obj: obj.expires() <= asOf)
def main():
cheeses = FileOf(Product).loadFile('cheesefile.txt')
cheeses.printAll()
cheeses.addNew()
expiredA = getExpired(cheeses) # prompt for expiration date
expiredB = getExpired(cheeses, "12/3/2011") # use given date
print("The expired items are:")
expiredB.printAll()
cheeses.saveFile('cheesefile.txt')
if __name__=="__main__":
main()
и образец файла cheesefile.txt:
ab:03/01/2011:10:brie
ac:03/01/2001:20:camembert
de:01/03/2011:30:brie
fg:01/03/2011:1:blink and it's gone
hi:01/05/2011:200:hard white cheddar
jkl:01/04/2011:60:jarlsberg