# Set#merge

**URL:** <https://www.ruby-forum.com/t/set-merge/99288>\
**Category:** Ruby\
**Created:** [January 31, 2006, 8:14am UTC](https://www.ruby-forum.com/t/set-merge/99288 "2006-01-31T08:14:41Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Joel\_VanderWerf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@Joel\_VanderWerf](https://www.ruby-forum.com/u/Joel_VanderWerf)\
**Post date:** [January 31, 2006, 8:14am UTC](https://www.ruby-forum.com/t/set-merge/99288/1 "2006-01-31T08:14:41Z")

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Can anybody explain why Set#merge is destructive, but Hash#merge is not?

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**Author:** ![Joel\_VanderWerf](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@Joel\_VanderWerf](https://www.ruby-forum.com/u/Joel_VanderWerf)\
**Post date:** [January 31, 2006, 10:51am UTC](https://www.ruby-forum.com/t/set-merge/99288/2 "2006-01-31T10:51:47Z")

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Joel VanderWerf wrote:

> Can anybody explain why Set#merge is destructive, but Hash#merge is not?

Probably the same reason that Array#delete is destructive, but  
String#delete is not.

Regards,  
Stefan