Perl Array - Unique 1

[not4google]

Hi all,

I have an array which muliple values in it and what I wanted to do is add the 5th element of the array to a new array which only stores unique values.

I would normally do this in shell scripting but wanted to learn some Perl so any suggestions would be much appreciated,

Thanks,

 

[KevinADC]

Lets see what perl code you have or have tried so far.



- Kevin, perl coder unexceptional!

 

[max1x]

Here's one way to do it. You will have to define the @array and @newArray.

foreach $val (@newArray) {
        if ($val != $array[4]) {
                 unshift @newArray, "$array[4]";
        print @newArray;
        last;
        }
}

 

[PC888]

max1x, it looks like that the code shown will add the element as long as the $newArray[0] does not equal to $array[4].
The following code should work, perhaps a little awkward.
# add fifth element if not a double in @newArray
my @array=(1,4,7,10,11);
my @newArray=(2,5,6,7,8,10,9);
my $duplicate=0;
my $size=@newArray;
for($i=0;$i<$size;$i++){
if($newArray[$i]==$array[4]){ $duplicate=1;}
}
if($duplicate==0){
push @newArray,$array[4];
print @newArray;
}

 

[KevinADC]

my @oldarray = qw(1 2 3 4 8 6 7);
my @newarray = qw(1 2 3 4 5 6 7);

unless (grep {$_ eq $oldarray[4]} @newarray) {
 push @newarray,$oldarray[4];
}

print "@newarray";

- Kevin, perl coder unexceptional!

 

[max1x]

PC888,

The foreach loop will check each element of @newArray with that of $array[4] (not just the first) and if they don't match, that's the only time it will append to the Beginning of the @newArray.

Though I like Kevin's way better, I'm not "unexceptional" like him .

 

[KevinADC]

if the arrays were gigantic another method would be beter to get out as soon as possible:

my @array=(some elements);
my @newArray=(millions of elements);
my $duplicate=0;
foreach my $line (@newarray){
  if($line eq $array[4]){
      $duplicate=1;
      [b]last;[/b]
}
unless($duplicate){
    push @newarray,$array[4];
}

- Kevin, perl coder unexceptional!

 

[PC888]

Max1x,

Perhaps I didn't express it correctly.

What I mean is that the code will insert the element and quit as soon as it finds a different array in newArray. If the first element happens to be different from array[4], then it will be inserted and quit without checking for duplication of the remaining elements of newArray.

For example,
my @array=(1,4,7,10,9);
my @newArray=(2,5,6,7,8,10,9);
will produce
925678109
which incurs a duplication of '9'.

On the other hand, we both agree that Kevin's code is concise and functional!

 

[max1x]

ur right, I overlooked that.

 

[PC888]

Looks like you work with Perl a lot from the number of answers you've given. I am new to Perl, so it's almost sure I will need some help from you some day!
Cheers.

 

[max1x]

Actually, I'm not in the IT industry and don't get to do much with Perl, but I like it. I learn from the likes of Kevin, Ishind, Kirsle and others, they are the true masters...

 

[PC888]

You're right, we're lucky to have the masters around, and most of all, helping out. I learn quite a bit by reading the posts and the answers.
Nice talking to you, cheers.

 

[WinblowsME]

[URL unfurl="true"]http://www.bayview.com/blog/2002/07/21/unique-arrays/[/URL]

 

[KevinADC]

WinblowsME

how would you apply that approach to the question?

- Kevin, perl coder unexceptional!