On Sun, Nov 21, 2010 at 11:02 PM, Alex Baranosky
<alexander.barano...@gmail.com> wrote:
> Hi guys,
> I'm trying to figure out how to use sort-by in reverse order.
> something like:
> (defn keyfn [p]
> (:last-name p))
> (sort-by keyfn persons)
> where persons is a map...
> I don't see it in the docs, what's the idiomatic way to do this?
What's wrong with just using (reverse (sort-by foo my-map))?
When you need a seq view, you can wrap it in reverse. When you don't,
the sort order is irrelevant anyway. (For a reverse-sorted seq of just
the keys, (reverse (sort-by foo (keys my-map))) works of course.)
Note that sorting a map sorts by keys; if the map is persons to
something else (e.g. account details or something) then you can sort
it by last name, or if the keys are things like {:first-name "foo"
:last-name "bar"} and the values are whole persons, but if you're
trying to sort on a field of the values that isn't a field of the
keys, you've got bigger problems than reversing the sort order.
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