[Tutor] Simple Question On A Method (in subclass)

[Chris Kavanagh]

On 10/23/2011 8:28 PM, Alan Gauld wrote:
> On 24/10/11 00:54, Chris Kavanagh wrote:
>
>>> Speaking of the last line of code, I have a question about that also.
>>> The last line should have been (without my error) {member.tell()}.
>>> My question is, why couldn't this last line have been {print member}??
>
> It could have been, but the output would have been different.
> When you call print it automatically calls the str() function on the
> arguments. So {print member} would actually print out
> {str(member)}. But str(member) is a message to say that member is an
> instance of a class, not a list of the attributes formatted in a
> specific way.
>
> Now Swaroop could have chosen to implement a __str__() method in the
> classes in which case print would have done what you expect. (But I
> guess he felt that would be too advanced at this stage in his tutor)
> Another option would have been to make tell() return a string rather
> than print it, in which case you could have used {print member.tell()}
>
>>> Every example of an iterator I've seen until this point of my learning,
>>> has had a print statement then the item variable.
>
> Thats just a coincidence with how you've seen iterators used. An
> iterator allows you to do anything you like to the items being iterated
> over. It just so happens that so far you have only seen them being
> printed. Printing is only one, and is far from the most common, use of
> iterators.
>
>>> the item variable to call the function {tell()}. This is sorta confusing
>>> to me. What if there was no function to print out the Student and
>>> Teacher variable??
>
> You would have to rely on the str() conversion - which will always print
> something, even if its not very helpful! Or, you could manually print
> the contents of the member - but that gets very complicated where you
> have mixed sub and superclasses in a single collection.
>
>  > How would the iterator been printed out in that
>> case??
>
> Being picky, you are not printing the iterator, you are printing the
> items returned by the iterator. But ignoring that, you would do one of
> the options I described above:
>
> 1) print the object using its built in str() convertion
> 2) create your own string conversion method (__str__() )
> 3) print the individual data members by hand
>
> Personally I would choose the second one, but modifying the code is not
> always possible, in which case, option 3 wins. Option 1 is usually
> pretty useless!
>
> HTH
>
Thanks so much for the help Alan. . .I'm not trying to beat this 
question into the ground, LOL, but let me see if I can ask it a better way.

So we have {member.tell} as the last line of code. So trying to 
understand this piece of code, {member} the variable is considered an 
object? Therefore we can combine it with a function {tell()} using dot 
notation?? Is this correct??? I haven't seen anything but an object 
combined with a function using dot notation. When I say "object", I mean 
an "object" created from a class. So I'm trying to figure out how we can 
combine the variable {member} with the function {tell}. Hope this 
question makes sense to you, LOL. Thanks again.