Re: hashtable - select by wilecard... is it doable?

From:

Patricia Shanahan <pats@acm.org>

Newsgroups:

comp.lang.java.programmer

Date:

Thu, 28 Sep 2006 15:11:47 GMT

Message-ID:

<TCRSg.3797$o71.1133@newsread3.news.pas.earthlink.net>

Hendrik Maryns wrote:

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Hash: SHA1

Dan Andrews schreef:

tak wrote:

Hi,

What is a data structure out there, that you can select by wilecard,
and also have fast retrievals?

like, if i have 4 keys, JOHN, JONATHAN, JOAN, TOM., and I want to do a
getKey by, "JO*", and that would return the values for the one that
matches JO* as either array, set, collection..etc...

thanks,
T

If you are only concerned about matching the first few characters
(starts with JO) then would a TreeSet<String> (that I refer to a treeSet
below) work?

    SortedSet<String> tailSet = treeSet.tailSet("JO");
    TreeSet<String> matchingSet = new TreeSet<String>();
    for (String s : tailSet) {
      if (!s.startsWith("JO")) {
        break;
      }
      matchingSet.add(s);
    }
    return matchingSet;

Just and idea and not sure if it is what you need.

He probably needs a TreeMap<String,Something>, but the principle remains
the same.

If it gets any more complicated than a TreeMap, it may be worth
separating the find-the-key-set problem from the map.

Patricia

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