Hm, google groups did not show my first reply to myself for a while,
and I thought it had gotten lost in the way, so I sent another post,
which can be safely ignored, in case anyone wonders what the
difference between the first and the second reply is - there is none,
fundamentally.
On Jul 10, 7:54 pm, Eugen Dück <eu...@dueck.org> wrote:
> Well, turns out string-like-coll-comparator has a bug:
>
> x=> (subseq (sorted-map-by string-like-coll-comparator (vec "ab") 1
> (vec "n") 2) > (vec "a"))
> NullPointerException clojure.lang.AFunction.compare (AFunction.java:
> 59)
>
> It can be fixed though:
>
> (defn string-like-coll-comparator
> [coll1 coll2]
> (or (first (drop-while zero? (map compare coll1 coll2)))
> (- (count coll1) (count coll2))))
>
> Now, is this the way to get the sorting behavior I want or is anyone
> aware of something simpler or more performant?
>
> On Jul 10, 6:09 pm, Eugen Dück <eu...@dueck.org> wrote:
>
>
>
>
>
>
>
> > Say I have this sorted map, using strings as keys:
>
> > x=> (sorted-map "ab" 1 "n" 2)
> > {"ab" 1, "n" 2}
>
> > When I do a subseq
>
> > x=> (subseq (sorted-map "ab" 1 "n" 2) > "aa")
> > (["ab" 1] ["n" 2])
>
> > I get back both entries.
>
> > Now if I do the same subseq on the same map, except that I turn all
> > strings into character collections, I only get the "ab" entry:
>
> > x=> (subseq (sorted-map (vec "ab") 1 (vec "n") 2) > (vec "aa"))
> > ([[\a \b] 1])
>
> > I guess that's fine, the length of collections is probably used first
> > and only if it differs would the actual entries be compared.
>
> > Using my own comparator to simulate the string comparison I can get
> > the string-like behavior:
>
> > (defn string-like-coll-comparator
> > [coll1 coll2]
> > (first (drop-while zero? (map compare coll1 coll2))))
>
> > x=> (subseq (sorted-map-by string-like-coll-comparator (vec "ab") 1
> > (vec "n") 2) > (vec "aa"))
> > ([[\a \b] 1] [[\n] 2])
>
> > Here's my question - is this the best way to get what I want?
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