java - Obtain key of a hashmap with a range of numbers as value -

i have hashmap<integer, float> entries:

 1 -> 0.127  2 -> 0.167  3 -> 0.207  4 -> 0.247  5 -> 0.237  6 -> 0.327  7 -> 0.367  8 -> 0.407  9 -> 0.447 10 -> 0.487 11 -> 0.527 12 -> 0.567 13 -> 0.607 14 -> 0.647 15 -> 0.652 

let suppose want key float 0.465 (which not existing value). 0.465 between 0.447 , 0.487, key 10.

the first thought came in mind achive 15 if/else if statements or switch statement. in view, wouldn't elegant , practical.

is there other way this?

a map not appropriate data structure. use treeset instead:

treeset<float> numbers = new treeset<>(); // populate set numbers, in order,  int index = numbers.headset(n).size() + 1; 

this perform well: treeset finds insertion point in o(log n) time (like binary search) , list returned view (a new list not created), whole operation lightweight.

also note elements don't need added in particular order - treeset internally maintains order searching fast.

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here's test code:

treeset<float> numbers = new treeset<>(arrays.aslist(     0.607f, 0.647f, 0.127f, 0.167f, 0.207f, 0.247f, 0.237f, 0.327f,     0.367f, 0.407f, 0.447f, 0.487f, 0.527f, 0.567f, 0.652f)); 

output:

10