RE: RE: Sorting an Array?

minor correction, you need a '->' in the $a in the sort:

@sorted = map {$_->[1]}
    sort { $a->[0] <=> $b->[0] }
    map { [$_[4],$_] } @unsorted;
[download]

and correct me if I'm mistaken (please), but isn't the Schwartzian Transform used in cases where it is necessary to modify the sort key? ie. dictonary sorting mixed case words.
/\/\averick

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RE: RE: RE: Sorting an Array? by awwaiid (Friar) on Jul 13, 2000 at 20:26 UTC
Thanks for the correction :) Naw, the transform doesn't have to modify the sort key... its more general purpose than that (though that is an excellent use). It is just a good algorithm for sorting (array based) data that is more complicated (and or a lot larger) than a plain array. Recently, for instance, I had an array of hashes, and used the transform to sort the array by the contents of one of the hash items. For instance, if we had a phone book or something, consisting of an array of hashes, each hash being an entry (`$phonebook[0]{firstname}` would access the firstname, for example) we could do the transform to sort by say... or something. `@sorted_phonebook = map {$_->[1]} sort {$a->[0] cmp $b->[0]} map {[$_{lastname},$_]} @phonebook;` [download] Now, we could indeed do a more complex grabbing of the field we are sorting by and/or a more complex sort algorithm, one in which we needed to modify the key even, but the transform is useful for this case as well. --awwaiid	[reply] [d/l] [select]

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RE: RE: RE: Sorting an Array?
by awwaiid (Friar) on Jul 13, 2000 at 20:26 UTC

Thanks for the correction :)

Naw, the transform doesn't have to modify the sort key... its more general purpose than that (though that is an excellent use). It is just a good algorithm for sorting (array based) data that is more complicated (and or a lot larger) than a plain array. Recently, for instance, I had an array of hashes, and used the transform to sort the array by the contents of one of the hash items.

For instance, if we had a phone book or something, consisting of an array of hashes, each hash being an entry ($phonebook[0]{firstname} would access the firstname, for example) we could do the transform to sort by say... or something.

@sorted_phonebook = map {$_->[1]}
  sort {$a->[0] cmp $b->[0]}
  map {[$_{lastname},$_]} @phonebook;
[download]

Now, we could indeed do a more complex grabbing of the field we are sorting by and/or a more complex sort algorithm, one in which we needed to modify the key even, but the transform is useful for this case as well.

[reply]
[d/l]
[select]