# Finding duplicates in an array

**URL:** <https://www.ruby-forum.com/t/finding-duplicates-in-an-array/95922>\
**Category:** Rails\
**Created:** [June 19, 2006, 9:38pm UTC](https://www.ruby-forum.com/t/finding-duplicates-in-an-array/95922 "2006-06-19T21:38:26Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![jjkiesch](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/bc79bd/32.png) [@jjkiesch](https://www.ruby-forum.com/u/jjkiesch)\
**Post date:** [June 19, 2006, 9:38pm UTC](https://www.ruby-forum.com/t/finding-duplicates-in-an-array/95922/1 "2006-06-19T21:38:26Z")

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an application i am working on sends emails to an array of users. it is  
possible for the user’s email to actually be in the array more than  
once.

i don’t have a real strong grasp of the ruby syntax yet, but is there an  
easy way to go through and either remove all of the duplicates or at  
least only send an email to that user once?

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**Author:** ![jjkiesch](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/bc79bd/32.png) [@jjkiesch](https://www.ruby-forum.com/u/jjkiesch)\
**Post date:** [June 19, 2006, 9:45pm UTC](https://www.ruby-forum.com/t/finding-duplicates-in-an-array/95922/2 "2006-06-19T21:45:35Z")

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i just found something in the reference guide on the ruby site.

previously i was using something like:

emailArr \<\< newEmail

but i saw this:

emailArr | [newEmail]

is this what i should do when creating the array? or is there a better  
way to accomplish what i need?

---

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**Author:** ![jjkiesch](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/bc79bd/32.png) [@jjkiesch](https://www.ruby-forum.com/u/jjkiesch)\
**Post date:** [June 19, 2006, 9:46pm UTC](https://www.ruby-forum.com/t/finding-duplicates-in-an-array/95922/3 "2006-06-19T21:46:27Z")

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On Monday, June 19, 2006, at 9:38 PM, Josh K. wrote:

> * * *
> 
> Rails mailing list  
> removed\_email\_address@domain.invalid  
> [http://lists.rubyonrails.org/mailman/listinfo/rails](http://lists.rubyonrails.org/mailman/listinfo/rails)

new\_array = some\_array.uniq

\_Kevin