I'm new to programming and have an assignment I've been working at for awhile. I understand defining functions and a lot of the basics but I'm kind of running into a brick wall at this point. I'm trying to figure this one out and don't really understand how the 'class' feature works yet. I'd appreciate any help with this one; also any help with some python resources that have can dummy down how/why classes are used. You've been going to work on a database project at work for sometime now. Your boss encourages you to program the database in Python. You disagree, arguing that Python is not a database language but your boss persists by providing the source code below for a sample telephone database. He asks you to do two things: Evaluate the existing source code and extend it to make it useful for managers in the firm. (You do not need a GUI interface, just work on the database aspects: data entry and retrieval - of course you must get the program to run or properly work He wants you to critically evaluate Python as a database tool. Import the sample code below into the Python IDLE and enhance it, run it and debug it. Add features to make this a more realistic database tool by providing for easy data entry and retrieval. import shelve import string UNKNOWN = 0 HOME = 1 WORK = 2 FAX = 3 CELL = 4 class phoneentry: def __init__(self, name = 'Unknown', number = 'Unknown', type = UNKNOWN): self.name = name self.number = number self.type = type # create string representation def __repr__(self): return('%s:%d' % ( self.name, self.type )) # fuzzy compare or two items def __cmp__(self, that): this = string.lower(str(self)) that = string.lower(that) if string.find(this, that) >= 0: return(0) return(cmp(this, that)) def showtype(self): if self.type == UNKNOWN: return('Unknown') if self.type == HOME: return('Home') if self.type == WORK: return('Work') if self.type == FAX: return('Fax') if self.type == CELL: return('Cellular') class phonedb: def __init__(self, dbname = 'phonedata'): self.dbname = dbname; self.shelve = shelve.open(self.dbname); def __del__(self): self.shelve.close() self.shelve = None def add(self, name, number, type = HOME): e = phoneentry(name, number, type) self.shelve[str(e)] = e def lookup(self, string): list = [] for key in self.shelve.keys(): e = self.shelve[key] if cmp(e, string) == 0: list.append(e) return(list) # if not being loaded as a module, run a small test if __name__ == '__main__': foo = phonedb() foo.add('Sean Reifschneider', '970-555-1111', HOME) foo.add('Sean Reifschneider', '970-555-2222', CELL) foo.add('Evelyn Mitchell', '970-555-1111', HOME) print 'First lookup:' for entry in foo.lookup('reifsch'): print '%-40s %s (%s)' % ( entry.name, entry.number, entry.showtype() ) print print 'Second lookup:' for entry in foo.lookup('e'): print '%-40s %s (%s)' % ( entry.name, entry.number, entry.showtype() ) I'm not sure if I'm on the right track but here is what I have so far: def openPB(): foo = phonedb() print 'Please select an option:' print '1 - Lookup' print '2 - Add' print '3 - Delete' print '4 - Quit' entry=int(raw_input('>> ')) if entry==1: namelookup=raw_input('Please enter a name: ') for entry in foo.lookup(namelookup): print '%-40s %s (%s)' % (entry.name, entry.number, entry.showtype() ) elif entry==2: name=raw_input('Name: ') number=raw_input('Number: ') showtype=input('Type (UNKNOWN, HOME, WORK, FAX, CELL): \n>> ') for entry in foo.add(name, number, showtype): #Trying to figure out this part print '%-40s %s (%s)'% (entry.name, entry.number, entry.showtype() ) elif entry==3: delname=raw_input('Please enter a name to delete: ') # #Trying to figure out this part print "Contact '%s' has been deleted" (delname) elif entry==4: print "Phone book is now closed" quit else: print "Your entry was not recognized." openPB() openPB()