[Tutor] Consolidate reused code blocks

[Kent Johnson]

On Wed, Apr 8, 2009 at 8:38 PM, David <david at abbottdavid.com> wrote:
> Hi Everyone,
>
> I have a simple todo list program with functions to add, delete, edit and
> print out a list of todo's. I need to understand how to remove the same
> blocks of code I use in each function. Should I create a class for the same
> block of code I am including in each function?

No, you can make functions to contain common code. You are sort of on
the right track with your load_todo() function, though it should
really be called save_todo().

> Here are two of the
> functions;
>
> def main():
>    print '\nYour current Todo list is: \n'
>    if os.path.exists('todo.dat'):
>        try:
>            fname = open('todo.dat', 'rb')
>            data = cPickle.Unpickler(fname)
>            todo = data.load()
>            load_todo(todo)

Not sure why you call load_todo() here, it writes back to the file you
just read.

You could have a real load_todo() that looks like this:

def load_todo():
  if (os.path.exists('todo.dat')):
    with open('todo.dat', 'rb') as fname: # with statement is simpler
than try/finally
      data = cPickle.Unpickler(fname)
      todo = data.load()
  else:
    todo = {}
  return todo

Then your main() could look like this:

def main():
   print '\nYour current Todo list is: \n'
   todo = load_todo()
   if todo:
           for k, v in todo.iteritems():
               print k, v[0], v[1]
   else:
       print "You have 0 todo's"
       menu()

Kent