Python "why" questions

[Roald de Vries]

On Aug 7, 2010, at 3:53 PM, D'Arcy J.M. Cain wrote:
> On Sat, 7 Aug 2010 15:37:23 +0200
> Roald de Vries <downaold at gmail.com> wrote:
>>> Would said beginner also be surprised that a newborn baby is zero
>>> years
>>> old or would it be more natural to call them a one year old?  Zero
>>> based counting is perfectly natural.
>>
>> A new born baby is in his/her first year. It's year 1 of his/her  
>> life.
>> For this reason, also "the year 0" doesn't exist. From the fact  
>> that a
>> baby can be half a year old, you derive that arrays should have  
>> floats
>> as indices?
>
> No.  You are giving me math and logic but the subject was common
> sense.  Common usage counts ages as years with the second year called
> "one year old" so zero based counting is common.  We don't tell Aunt
> Martha that little Jimmy is in his third year.  We say that he is two
> years old and Aunt Martha, a non-programmer, understands exactly what
> we mean.  Using one-based counting (first year, second year, etc.)
> would be the unnatural thing, would confuse Aunt Martha and make her
> spoil her apple pie and no one wants that.

My point is that "0" in "Jimmy is 0" doesn't play the same role as in  
"item 0 of a sequence".