Lists and Tuples

[Douglas Alan]

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To: bokr at oz.net (Bengt Richter)
Subject: Re: Lists and Tuples
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From: Douglas Alan <nessus at mit.edu>
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bokr at oz.net (Bengt Richter) writes:

> On Thu, 04 Dec 2003 21:45:23 -0800, David Eppstein
> <eppstein at ics.uci.edu> wrote:

>> That's true, but another answer is: you should use tuples for short
>> sequences of diverse items (like the arguments to a function).  You
>> should use lists for longer sequences of similar items.

> I'm curious what you're getting at. I.e., what does diversity or
> similarity have to do with the choice?

Nothing really, except by idiom.  When people use "should" here, I
think they are over-generalizing.  Most of the time, records (short
and heterogenious) are used in a read-only fashion, and long
homogenous sequences are used in a read-write fashion.  But when
people characterize this tendency with a "should", I think they are
making a thinko.  There are times when you need to modify a record and
consequently might use a dictionary or list, rather than a tuple,
and there are also times when you will never want to modify a long,
homogenous sequence, in which case many people would find it more
elegant to use a tuple than to use a list.

The reason for the "should" is probably because, I imagine, Guido had
in mind mostly multiple return values from function, and the like,
when he put tuples into the language.

|>oug