(Container)Map with array keys

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Bananach
Bananach on 19 Apr 2016
Answered: Titus Edelhofer on 19 Apr 2016
I need a Map whose keys are arrays of integers. MATLAB's Containers.Map does not allow array keys. The implementation with Java's HashMap below also does not work.
jm=java.util.HashMap();
a=[1 1];
jm.put(a,1)
jm.containsKey(a)
I thought that an ad-hoc solution, for fixed array length 2, would be to convert the array into a scalar double (in a reversible way). If there is no other way, could anyone help me doing this?

Accepted Answer

Titus Edelhofer
Titus Edelhofer on 19 Apr 2016
Hi,
no, there is no "nice" way of doing this. Using a scalar should work fine though:
a = [42 23];
% assume that your indices fit into [0..65535] (example)
key = a(1)*65536 + a(2);
m = containers.Map({key}, {'Bananach'});
% access works
m(key)
% and it's reversible
aFromKey = [floor(key/65536), rem(key, 65536)]
Titus

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