Is there a way to get all keys from a value in a multimap?

Question

Say I have a guava Multimap. I have a value, "Foo", that may belong to one or more keys. Is there any way I can figure out which keys contain an entry "Foo"?

Cyrille Ka · Accepted Answer · 2013-02-22T20:04:22.390

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You can invert the Multimap. For this you can use the method Multimaps.invertFrom.

For example, if your Multimap is a Multimap<String, String>

Multimap<String, String> invertedMultimap = Multimaps.invertFrom(myMultimap, ArrayListMultimap.<String, String>create());

edited Feb 22 '13 at 20:04

answered Feb 22 '13 at 19:42

Cyrille Ka

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I knew there had to be an easy way to do this! Thanks! :) – Jason Thompson Feb 22 '13 at 19:51
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If you've got an `ImmutableMultimap`, it has a built-in `inverse()` method. – Louis Wasserman Feb 22 '13 at 20:14

score 7 · Answer 2 · answered Feb 23 '13 at 18:01

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If you have an ImmutableMultimap, which is a good idea whenever possible, you can call .inverse().get(v) on it.

answered Feb 23 '13 at 18:01

Kevin Bourrillion

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Is there a way to get all keys from a value in a multimap?

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