remove repeating elements in array

[mani5int]

hi people can any one tell me how do i remove elements in an array which repeat more than 4 times
i tried this for single time but how do i get it for 4 times
%seen = ();
@unique = ();

for each $elem (@array)
next if $seen{$elem}++
push @unique, $elem (@array)

plzzzzzz help me in this regard

 

[PaulTEG]

That's using a hash to remove duplicates, but for what you want you need to walk a sorted array, and if the element occurs more than 4 times, splice it from the array

sort @array;
$last_seen='';
for (@array) {
  if ($last_seen eq $_) {
    $counter++;
    if ($counter >=4 ) {
      #I'll leave the splicing up to the reader
    }
    $last_seen=$_;
  } else {
    $last_seen=$_;
    $counter=1;
  }
}

Not tested ...

Paul
------------------------------------
Spend an hour a week on CPAN, helps cure all known programming ailments ;-)

 

[KevinADC]

your question is vague, can you give an example of what you mean?

------------------------------------------
- Kevin, perl coder unexceptional!

 

[brigmar]

I read your question as having two possible meanings:

1: Remove the 5th and onward duplicates, leaving the first 4 in the array

foreach $val (@array) {
  push @deduped, $val if $seen{$val}++ <4;
}

This is simply an extension of the original code, pushing 'as we go'.

2: Remove all matching elements that have 5 or more repetitions.

$seen{$_}++ foreach (@array);
@deduped = grep{ $seen{$_}<=4 } @array;

This is a little different in that it populates the hash fully before creating the deduped array.

 

[MillerH]

This would just be a variation of:

perlfaq4 - How do I remove duplicate elements from a list or array?

[url=http://perldoc.perl.org/functions/my.html][black][b]my[/b][/black][/url] [blue]%seen[/blue] = [red]([/red][red])[/red][red];[/red]
[black][b]my[/b][/black] [blue]@filtered[/blue] = [url=http://perldoc.perl.org/functions/grep.html][black][b]grep[/b][/black][/url] [red]{[/red] [blue]$seen[/blue][red]{[/red] [blue]$_[/blue] [red]}[/red]++ < [fuchsia]4[/fuchsia] [red]}[/red] [blue]@array[/blue][red];[/red]

- Miller

 

[AMiSM]

Assign all the elements as keys in a hash, then extract the keys from the hash. The redundancies will cancel:


foreach ( @array ) {
$hash{$_} = 1;
}

@array = keys(%hash);