Counting within an array

ddrew78 has asked for the wisdom of the Perl Monks concerning the following question:

Greetings Monks, I have a file that looks something like this:

CS
MS
CS
AT
AV
MS
[download]

What I need to do is count the occurrance of each, so the output based on the above should be

CS1
MS1
CS2
AT1
AV1
MS2
[download]

I figured the easiest way would be to do this using an array, but what I have below does not give me what I need.

open(PBXNUM1, ">pbxnum1");
open(MYINPUTFILE, "pbxnum");

    $nt = 0;
    $ms = 0;
    $ap = 0;
    $cs = 0;
    $em = 0;
    $at = 0;
    $av = 0;
    $to = 0;
    
    while (<MYINPUTFILE>) {
        my($line) = $_;
        chomp($line);
        
        $nt++;
        $ms++;
        $ap++;
        $cs++;
        $em++;
        $at++;
        $av++;
        $to++;
        
    @mypbx = ('NT', 'MS', 'AP', 'CS', 'EM', 'AT', 'AV', 'TO');
    foreach $mypbx (@mypbx) {
        print PBXNUM1 "$line$mypbx\n";
        }
    }
[download]

Any suggestions?

Comment on Counting within an array Select or Download Code

Replies are listed 'Best First'.
Re: Counting within an array by happy.barney (Friar) on Nov 30, 2010 at 13:48 UTC
use hash: `my %hash; while (<MYINPUTFILE>) { chomp; $hash{$_} ++; } $\ = "\n"; while (my ($k, $v) = each %map) { print $k, $v; }` [download]	[reply] [d/l]
Re^2: Counting within an array by kennethk (Abbot) on Nov 30, 2010 at 14:04 UTC
In order to meet the posted spec (output on every line), you can move the print statement into the while loop: `my %hash; while (<MYINPUTFILE>) { chomp; $hash{$_} ++; print "$_$hash{$_}\n"; }` [download]	[reply] [d/l]
Re^3: Counting within an array by ddrew78 (Beadle) on Nov 30, 2010 at 14:12 UTC
That works like a charm, thank you very much.	[reply]
Re: Counting within an array by locked_user sundialsvc4 (Abbot) on Nov 30, 2010 at 14:22 UTC
It is very useful to note how, in the first response, the statement e.g. `$$somehash{$somekey}++` will automagically create a new hash-element, with a value of 1, if such a key does not presently exist. In fact, “incrementing an `undef` value” works in-general, producing a value of 1. A delightful example of “DWIM = Do What I Mean.” One tiny consideration if you happen to be reading strings from a file: don’t forget to `chomp`. Otherwise, the strings you read might contain invisible “newline” characters which can make for irritating annoyance-bugs.
Re: Counting within an array by ambrus (Abbot) on Dec 01, 2010 at 11:01 UTC
`awk '{ print $0(++a[$0]) }'` [download] Just kidding. Use the perl solution above instead.	[reply] [d/l]