On 06/08/2011 11:59 PM, Larry Hudson wrote:
On 06/08/2011 01:09 PM, Cathy James wrote:
I am almost there, but I need a little help:
I would like to
... <deleted text>
Here's one possible replacement. There are many other approaches as well.
(This leaves the individual dogs as a (name, breed) tuple. It could be modified
for other
definitions of a dog. -- Exercise left for the reader...) ;-)
... <more deleted text>
In thinking about this some more, I thought a dictionary instead of a list would be a better fit
for this example. For one thing, it allows accessing the dogs by name instead of an arbitrary
index number. But remember that a dictionary is unordered -- it won't be displayed in the same
order that the entries were made.
Here's this approach, rewritten (and slightly expanded) using a dictionary.
class DogKennel:
def __init__(self):
"""Dog names/breeds kept in a dictionary"""
self.dogs = {}
def addDog(self):
"""Add a single dog to the dictionary"""
name = input("Enter dog's name: ")
if name == "": # Abort with empty input
return False
breed = input("Enter dog's breed: ")
if breed == "": # Abort here if needed also
return False
self.dogs[name] = breed
return True
def makeKennel(self):
"""Add multiple dogs (a pack?) to the dictionary"""
while self.addDog():
pass
def getDog(self, name=""):
"""Get the dog's breed by its name"""
if name in self.dogs:
return self.dogs[name]
else:
return None
def display(self):
"""Display all the dogs in the kennel (the dictionary)"""
i = 1
for dog in self.dogs.keys():
print("%2d. %s: %s" % (i, dog, self.dogs[dog]))
i += 1
# Note this is a normal function, NOT a member function of DogKennel.
# It probably should go in the __main__ section to keep it separate from
# the DogKennel class. (This would be significant only if you're going
# to import the DogKennel class into other programs.)
def yesno(prompt = ""):
"""Get a yes or no answer. Returns True if yes, False if no"""
if prompt != "":
prompt = prompt + " (y/n) "
while True:
ans = input(prompt).upper()
if ans != "": # Answer is not empty
if ans[0] == 'Y': # 1st char is 'Y'?
return True
if ans[0] == 'N': # 1st char is 'N'?
return False
# Otherwise loop back for another go
if __name__ == "__main__":
dogs = DogKennel()
dogs.makeKennel()
dogs.display()
if yesno("Add more dogs?"):
dogs.makeKennel()
print("The kennel now contains")
dogs.display()
while True:
name = input("Which dog do you want? ")
if name == "":
break
breed = dogs.getDog(name)
if breed != None:
print(name, "is a", breed)
#---------------
I hope studying this (and my previous) examples help you understand things
better.
Keep at it... It will sink in with a little effort. :-)
I also hope my rather verbose answers give you a little insight about the sort of things you
need to consider when designing your programs.
-=- Larry -=-
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