Op 2005-11-28, Aahz schreef <[EMAIL PROTECTED]>:
> In article <[EMAIL PROTECTED]>,
> Christoph Zwerschke <[EMAIL PROTECTED]> wrote:
>>
>>For instance, I just wanted to use the index() method on a tuple which
>>does not work. It only works on lists and strings, for no obvious
>>reason. Why not on all sequence types?
>
> Because Guido believes that tuples should be primarily used as
> lightweight replacements for C structs. Therefore they have minimal
> functionality.
I find that a bit contradictory with the fact that if you want list like
structures as a dictionary key, you are mostly advised to cast them
as tuples.
So suppose I want a dictionary, where the keys are colours, represented
as RGB triplets of integers from 0 to 255. A number of things can be
checked by index-like methods.
e.g.
def iswhite(col):
return col.count(255) == 3
def primary(col):
return col.count(255) == 1 and col.count(0) == 2
def secondary(col):
return col.count(255) == 2 and col.count(0) == 1
So, what should I use to implement this? Whether I choose
lists or tuples, I will end up either copying a lot from
lists to tuples or vice versa, to get the functionality
I need, or I will have to implement functionality myself
that basically is already in the language.
I also find the use of C-structs and tuples completly different.
If I need a C-struct like object, I go for Bunch, Rec or something
similar. Something that uses field identifiers to address components,
Not something that uses indexing.
--
Antoon Pardon
--
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