[Tutor] Code critique please (OOP strategy)
Michael P. Reilly
Mon, 31 Dec 2001 13:04:38 -0500
On Mon, Dec 31, 2001 at 08:46:48AM -0600, Timothy Wilson wrote:
> > you could make a menu class or function, but all that would do is move the
> > code out of main.
> Here's an example:
> The main() function contains the following code to delete a stock:
> elif choice.upper() == 'D':
> ticker = raw_input("Delete which stock (type a ticker symbol): ")
> for stock in p.contents:
> if stock.ticker == ticker.upper():
> print "Removed %s" % stock.ticker
> The delStock method is:
> def delStock(self, stock):
> self.modified = 1
> Is is correct to ask for the ticker symbol in the 'elif' or should I do
> that in 'delStock'? My reason for doing it the way I did was to make the
> code as reusable as possible. That may or may not be a valid reason in
> this case. I'd appreciate feedback on this point.
You might want to look at the cmd module; it's design is meant for
user keyboard input.
prompt = '(O)pen existing portfolio or (M)ake a new one? '
self.portfolio = None
def do_M(self, args):
self.portfolio = Portfolio()
def do_O(self, args):
file = raw_input("filename: ")
self.portfolio = Portfolio(file)
prompt = '(A)dd/(D)elete stocks, (S)ave file, (U)pdate, ' \
'(R)eport, or (Q)uit? '
def __init__(self, portfolio):
self.portfolio = portfolio
def do_A(self, args):
ticker = raw_input("Ticket symbol: ")
companyname = raw_input("Company name: ")
def do_D(self, args):
then you create new instances of these classes:
cmd = PortfolioCmd()
cmd.onecmd() # only one prompt and return
if cmd.portfolio is not None:
This makes things a bit more extensible and teaches your students to
reuse library classes.