APM: Sparse arrays

[jeremy]

I simply increment a counter at the bottom of the loop.
I've added a print section so you can see what happens.

 
$ary[100] = 1;
$ary[100000] = 2;
$ary[1000000] = 3;
 
$count = 0;
foreach $elt (@ary) {
        $some_value = $elt;
        $the_index = count;                     # how do I get this
information?
 
        if( $some_value ){
            print "\$ary[ $count ] -> $some_value\n";
        }
 
        $count++;
}


As far as this little section of code being a CPU hog  ....I don't know
what to say.  Does it really take days to complete?  On any modern
system this ought to finish in a couple of seconds  ...maybe 3.  In
fact,  on my machine it took 1.315s according to the time function.  The
machine is a 1.4 gig P4 with 921 MB SDRAM.  Is you machine very old?

Jeremy

On Thu, 2003-07-10 at 08:00, Brian Michalk wrote:
> Let's say I have a sparse array:
> $ary[100]=1;
> $ary[100000]=2;
> $ary[1000000]=3;
> 
> Now, I want to iterate over the array, either from lowest to highest array
> index, and still retain the index of the element returned.  How do I do
> that?
> 
> foreach $elt (@ary) {
> 	$some_value = $elt;
> 	$the_index = ????????;			# how do I get this information?
> }
> 
> 
> This algorithm is chewing up CPU time, causing the process to take days to
> complete... the dataset is several gigabytes large.
> 
> Using a hash, and sorting the keys will not give me a performance benefit.
> 
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