[Israel.pm] Perl Advocacy

Uri Bruck bruck at actcom.net.il
Wed Dec 29 14:23:22 PST 2004


Gabor Szabo wrote:

> 
> 
> I am not that coninced that having a unified view of hashes and array
> (which are then basically hashes with only numbers as keys)
> is a bad thing. It does hide some complexity (and produces a speed 
> penalty I guess).
> 
> Nothing would happen if
> 
>     keys %myhash;
> 
> would always return the keys sorted numerically.

I don't know the php internals on this, but the way it looks from the 
php programmer's pov is that adding a key to a hash implicitly creates a 
numerical index for that key.

Off hand I can think on one srting example where I'd a hash with 
numerical keys rather than an array.
Suppose I need to retrieve a set of values, each is associated with a 
number and I want to sort them.
One way is to stored each value at $array[$number]
Now suppose I know the numbers are not consecutive, I also know that for 
some cases I'll have big gaps. F'rinstance
1,2,10000
Using an array for that means that I've got a big empty array. Using a 
hash with those numbers as keys gives me the results I want with a much 
lower storage overhead.
If hashes and arrays are unified, I don't have that option.

> 
> 
> They still cannot have arrays as keys to arrays so Python must be
> superior to PHP as well.
> 
> http://il.php.net/manual/en/function.array.php
> 
> Gabor
> _______________________________________________
> Perl mailing list
> Perl at perl.org.il
> http://perl.org.il/mailman/listinfo/perl


-- 
Thanks,
Uri
http://translation.israel.net



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