in reply to Re^2: Sorting an array of hashes and filenames
in thread Sorting an array of hashes and filenames

That sorted it perfectly: Exactly as you told it to.

By the hash values, not the keys. The values of the hash (as you've constructed it) are the filenames, and if you'll notice, those are precisely in order.

Take out the {$file_hashes{$a} cmp $file_hashes{$b}}. It isn't what you want. (If you really want to put something there, put in {$a cmp $b}, but that's the default...

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Re^4: Sorting an array of hashes and filenames
by learningperl01 (Beadle) on Jan 14, 2009 at 23:28 UTC
    actually I was trying to sort on the first column only (the hash values) not the file names. How do I just sort on the first column, but still print the hash and the file name but sorted based on the hashes. thanks for all the help once again
[reply]

      Ok, we've got a problem of terminology here: You have a hash (perl) which contains keys and values. Your data is filenames and hashes of the files. The keys of your hash (perl) are the hashes (file) of your files. The names of the files are the values of the hash (perl).

      Here is your data structure:

      %file_hashes = ( $hash1 => $filename1,
                 $hash2 => $filename1, );

      [download]

      This means that keys returns ($hash1, $hash2). And that ($file_hashes{$hash1} eq $filename1).

      So, when you type sort { $file_hashes{$a} cmp $file_hashes{$b} } keys %file_hashes you are sorting your list of hashes (file) by the values of the hash (perl). Which are your filenames.

      You want to sort the list of hashes (file). Which is the keys of your hash (perl). Which is sort keys %file_hashes. Try it. It will work.

      Then go read perldata five or six times. It's not the best introduction to the subject (it's designed more as a reference), but it is thorough.

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