in reply to finding duplicate data

use a hash to count the number of each string occurance. 
#!/usr/bin/perl

while (<DATA>){
  chomp;
  $h{$_}++;  
}

for ( sort grep { $h{$_} != 1 } keys %h ) {
  print "$_\n";
}

__DATA__
A(01) 
B(02) 
C(03) 
A(01) 
D(04) 
E(05)

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Boris

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Re: Re: finding duplicate data
by harry34 (Sexton) on Jan 21, 2004 at 11:23 UTC
    That works great !.
    What is the second part of the code doing ?
    i.e. how is it working ?
[reply]
      Which part has you puzzled? grep? for () implicitly setting $_? (If the former, you should be able to run "perldoc -f grep" to get a description of what grep does. If for some reason you have a broken perl that doesn't include perldoc, try here.)
[reply]
        What if I have an array called (@hydrogen_split).
        Could I not write your code like this ? 

        foreach $i(0..@hydrogen_split){             
    chomp;
    $hydrogen_split{$key}++;
}

for ( sort grep { $hydrogen_split{$key} !=1 } keys %hydrogen_split){
print "$key\n";
}

        [download]
[reply]
[d/l]

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