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From: Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: Is there a better way to group and sort objects?
Date: Wed, 8 Aug 2018 06:57:33 -0400
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On 8/8/2018 4:20 AM, Martin Gregorie wrote:
> On Tue, 07 Aug 2018 06:00:19 -0700, Eric Douglas wrote:
> 
>> I want to combine and sort objects by key properties and merge their
>> secondary properties.  Is there a better way?  This is what I came up
>> with..
>>
> Given your ..and sort... requirement, I'd use a TreeMap rather than a
> HashMap because storing items in key sequence is implicit. In addition,
> its search efficiency rises as the tree gets bigger; if the treemap
> contains 2**23 entries a worst case search only does 23 key comparisons.

     ... except that he sorts on a field of the mapped values,
not on the map keys.  Specifically, if he has two instances with
`var1' values of 2 and 10 they will sort in that order, but
their map keys will sort in the order "10" followed by "2".

-- 
esosman@comcast-dot-net.invalid
Eight hundred ninety-six days to go.