[Tutor] class initialization with a lot of parameters

[C.T. Matsumoto]

This reply is also to Alan's suggestion to provide more context.

The situation concerns databases, where in one schema table I've got a
'compare list'.
This list provides defines 2 tables that need to be paired and then
compared. Before
any comparing happens I 'filter' the compare list doing several validation
tests. Once
all the test succeed (exists, with the necessary things to compare) I'm left
with the
information describing the 2 tables:

reference_table_name
reference_dburi
reference_rows
test_table_name
test_dburi
test_rows
keys

It is with this information that I wanted to create a class object. Filling
a 'master list'
of 'CompareItem' objects.

Cheers,

T

On Tue, Nov 10, 2009 at 1:05 AM, Dave Angel <davea at ieee.org> wrote:

> C.T. Matsumoto wrote:
>
>> Hello All,
>>
>> I'm making a class and the parameters I'm feeding the class is getting
>> quite
>> large. I'm up
>> to 8 now. Is there any rules of thumb for classes with a lot of
>> parameters?
>> I was thinking
>> to put the parameters into a tuple and then in the __init__ of the class,
>> iterate over the tuple
>> and assign attributes.
>>
>> <snip>
>>
>>
>>
> Don't do it.  Putting the parameters into a tuple only makes sense if
> they're somehow related to each other.  And if all the parameters are in the
> tuple, all you've done is to add another parenthesis pair around the
> argument list.
>
> Now, if the parameters are related to each other (like the coordinates of
> an n-dimensional point), then it makes sense to group them.  As Alan said, a
> class can be good for that.  So can tuples, but only if there's some
> connection, or if they already were being treated as a tuple.
>
> Note that if you want to declare your parameters as a tuple, you can use
> the * notation in the parameter list.  And if you want to pass the arguments
> as a tuple, you can use the * notation in the argument list.  Or both.  But
> you need to have a reason, other than "too many parameters."
>
>
> DaveA
>
>


-- 
Todd Matsumoto
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