From: Joe Van Dyk <joevandyk@...>
Date: 2005-10-17T13:30:38+09:00
Subject: Re: How to get non-unique elements from an array?

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On Oct 16, 2005, at 7:07 PM, Explosiv0SX wrote:

> You could just sort the array, then iterate. If the previous  
> iteration value is equal to the current, you have a non-unique.  
> This would work with string or numeric data types.
>
> Rick
>
> On Oct 16, 2005, at 9:44 PM, Lyndon Samson wrote:
>

Or, probably not efficient, but:

irb(main):031:0> a
=> [1, 2, 3, 4, 5, 5, 3]

irb(main):032:0> a.find_all { |x| a.find_all { |y| y == x }.size >  
1 }.uniq
=> [3, 5]

>
>> Funny, doesnt work when an item in the array > 10...
>>
>> Plus, reading the documentation ( doh! ) I can access a Bignum bit  
>> with []
>>
>>
>> On 10/17/05, Lyndon Samson <lyndon.samson@gmail.com> wrote:
>>
>>
>>>
>>> Not very elegant, but a different approach...
>>>
>>> bn = bn2 = 0
>>> a.each {|el|(bn2 |= (1<<el) if (bn & ( 1<<el) ) != 0) | bn |=  
>>> (1<<el) }
>>> 0.upto(a.length) { |bitNdx| puts bitNdx if (bn2 & ( 1<<bitNdx )) ! 
>>> = 0 }
>>>
>>>
>>>
>>>
>>>
>>
>>
>> --
>> Into RFID? www.rfidnewsupdate.com <http://www.rfidnewsupdate.com>  
>> Simple,
>> fast, news.
>>
>>
>
>
>

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