Greetings Monks,
I can't seem to find a way to determine the key of an array which is closest to a value. My data is essentially a bell shaped curve that I will eventually want to do some math on. I am trying to create a simple "full width at half max" type analysis. I am able to easily locate the maximum value and associated key in the hash, but what I am getting stuck on is how to determine the keys (one on each side of max) at which has a value closest to $hash{$max/2}.

My hash has the following values (sorted to make it easier to look at): 

-4 => 0 
-3.9 => 0 
-3.8 => 0 
-3.7 => 1 
-3.6 => 0 
-3.5 => 1 
-3.4 => 0 
-3.3 => 0 
-3.2 => 5 
-3.1 => 19 
-3 => 23 
-2.9 => 50 
-2.8 => 43 
-2.7 => 28 
-2.6 => 72 
-2.5 => 165 
-2.4 => 302 
-2.3 => 168 
-2.2 => 260 
-2.1 => 151 
-2 => 13 
-1.9 => 1 
-1.8 => 0 
-1.7 => 0 
-1.6 => 0 
-1.5 => 0 
-1.4 => 0 
-1.3 => 0 
-1.2 => 0 
-1.1 => 0 
-1 => 0

[download]
Step1: max value (302) has a key of "-2.4".
Step2: 302/2 = 151
Step3: Looking for keys -2.5 and -2.1

Any Suggestions?

I hope this makes sense
Thanks

In reply to Finding hash key related to closest value by nanophd

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