Hash table

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ruds - 25 May 2007 07:00 GMT

hi,
I want to know how can i retrive a key from the given value from a
hash table?
suppose my table conatins:
KEY VALUE
1 3
2 10
3 12
4 15
if i have value 10 how do i get its corresponding key??

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Shane - 25 May 2007 07:04 GMT

> hi,
> I want to know how can i retrive a key from the given value from a
[quoted text clipped - 6 lines]
> 4 15
> if i have value 10 how do i get its corresponding key??

The same way you knew where to insert the other values into your hash?

Signature

Math problems? Call 1-800-[(10x)(13i)2]-[sin(xy)/2.362x].

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Thomas Schodt - 25 May 2007 07:37 GMT

> hi,
> I want to know how can I retrive a key from the given value from a
> hash table?

suppose your table contains:
KEY VALUE
1 10
2 10
3 20
4 20
if you have value 10 which is its corresponding key?

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Mike Schilling - 25 May 2007 08:40 GMT

> hi,
> I want to know how can i retrive a key from the given value from a
[quoted text clipped - 6 lines]
> 4 15
> if i have value 10 how do i get its corresponding key??

You can iterate throught the set of entries (Map.entrySet()), looking for a
match. Or, if the values are unique, you can create a second hash table
that reverses keys and values, and look it up directly.

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Roedy Green - 25 May 2007 09:35 GMT

>hi,
>I want to know how can i retrive a key from the given value from a
[quoted text clipped - 6 lines]
>4 15
>if i have value 10 how do i get its corresponding key??

see http://mindprod.com/jgloss/hashtable.html
http://mindprod.com/jgloss/hashmap.html
--

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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Hendrik Maryns - 25 May 2007 14:51 GMT

Roedy Green schreef:

>> hi,
>> I want to know how can i retrive a key from the given value from a
[quoted text clipped - 6 lines]
>> 4 15
>> if i have value 10 how do i get its corresponding key??

Jakarta Commons Collections defines the BidiMap interface and gives some
implementations.

I can provide you with a generified version if you wish.

H.
- --
Hendrik Maryns
http://tcl.sfs.uni-tuebingen.de/~hendrik/
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