Question about ++ and hash value

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

Hi perl peeps, I have this code to find the numbers of numbers for each entry:

 my %hash;
    while(my $line=<>){

    chomp $line;
    chop $line;
    $hash{$line}++;
                   }

             print %hash;
[download]

My Q is what goes on here : $hash{$line}++; ?

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Re: Question about ++ and hash value by grep (Monsignor) on Dec 08, 2007 at 23:46 UTC
`++` is the auto-increment operator. `$hash{$line}` is a hash assignment So `$hash{$line}++` auto-increments the value of `$hash{$line}` Also please read Writeup Formatting Tips and use `<code>` tags around your code grep `One dead unjugged rabbit fish later...`	[reply] [d/l] [select]
Re^2: Question about ++ and hash value by ada (Novice) on Dec 09, 2007 at 00:01 UTC
Ok thanks, so I guess that each value increases by how many occurances there are of the key in the hash. Is this the understanding?	[reply]
Re: Question about ++ and hash value by swampyankee (Parson) on Dec 09, 2007 at 00:32 UTC
It's counting the number of times a given line appears in a file. `$hash{$line}++` is incremented by 1 (set to one automagically on the first instance of $line) each time $line (well, $line minus the piece removed by chop) appears. emc Information about American English usage here and here. Any Northeastern US area jobs? I'm currently unemployed.	[reply]
Re^2: Question about ++ and hash value by ada (Novice) on Dec 09, 2007 at 00:37 UTC
Ok thanks so are these increments stored as values of keys? Ada x	[reply]
Re^3: Question about ++ and hash value by swampyankee (Parson) on Dec 09, 2007 at 00:47 UTC
Yes emc Information about American English usage here and here. Any Northeastern US area jobs? I'm currently unemployed.	[reply]
Re^3: Question about ++ and hash value by ysth (Canon) on Dec 09, 2007 at 07:36 UTC
The keys of the hash are the lines that appear in the input (less the character removed by chop). The values are how many times each line has been encountered. -- CollegeGear.com - more than just college gear (though, yes, we have college-branded teddy bears)	[reply]

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