# Hash of arrays - initialization (was Re: Beyond YAML? (scali

**URL:** <https://www.ruby-forum.com/t/hash-of-arrays-initialization-was-re-beyond-yaml-scali/103294>\
**Category:** Ruby\
**Created:** [May 3, 2007, 10:41pm UTC](https://www.ruby-forum.com/t/hash-of-arrays-initialization-was-re-beyond-yaml-scali/103294 "2007-05-03T22:41:07Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Bil\_K](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/848f3c/32.png) [@Bil\_K](https://www.ruby-forum.com/u/Bil_K)\
**Post date:** [May 3, 2007, 10:41pm UTC](https://www.ruby-forum.com/t/hash-of-arrays-initialization-was-re-beyond-yaml-scali/103294/1 "2007-05-03T22:41:07Z")

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Brian C. wrote:

> samples[tag] ||= []  
> samples[tag] \<\< sample
> 
> And you can probably combine:
> 
> (samples[tag] ||= []) \<\< sample

Thanks; I figured the magic || operator was somehow  
involved, but I still don’t have that thing memorized…  
yet more aggressive incompetence. 🙂

Thanks again,