Re: deleting from the memory

[roboticus]

programmer.perl:

As davido mentions, deleting from a *large* list may be a bit slow. The algorithm I use (only works when the order isn't important) is to copy the last item in the list on top of the entry to delete, and then truncate the last item from the list:

#!/usr/bin/perl                                                       
+          
use strict;    
use warnings;  
use Data::Dumper;
               
my @stuff = (qw(Chem Bio Maths C++ Java));
               
print "BEFORE: ", join(", ", @stuff), "\n";
my $i = int(@stuff * rand);
print "Removing item $i\n";
               
if ($i != $#stuff) {
    $stuff[$i] = $stuff[-1];
}              
$#stuff = $#stuff-1;
               
print "AFTER: ", join(", ", @stuff), "\n";

Running this a few times gives me:

$ perl t.pl
BEFORE: Chem, Bio, Maths, C++, Java
Removing item 4
AFTER: Chem, Bio, Maths, C++

$ perl t.pl
BEFORE: Chem, Bio, Maths, C++, Java
Removing item 2
AFTER: Chem, Bio, Java, C++

$ perl t.pl
BEFORE: Chem, Bio, Maths, C++, Java
Removing item 3
AFTER: Chem, Bio, Maths, Java

Update: Forgot some brackets (on davidos name ... almost did it again!)

...roboticus

When your only tool is a hammer, all problems look like your thumb.