my @arr1;
while ( <> ) {
    my @arr = split ',', $_;
    ( push @arr1, $arr[0] ) if  $arr[2] eq 'particular';
}

##</code><code>##

my @arr1 = grep { @{$_}[2] =~ /particular/ } @arr;

##</code><code>##

my @arr1 = grep { %{$_}{'FILETYPE'} eq 'particular' } @arr;