# How to create classes automatically

**URL:** <https://www.ruby-forum.com/t/how-to-create-classes-automatically/101154>\
**Category:** Ruby\
**Created:** [August 3, 2006, 2:21pm UTC](https://www.ruby-forum.com/t/how-to-create-classes-automatically/101154 "2006-08-03T14:21:49Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 3, 2006, 2:21pm UTC](https://www.ruby-forum.com/t/how-to-create-classes-automatically/101154/1 "2006-08-03T14:21:49Z")

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hi

let’s say I have a string with a class name as a value.  
I want to create a new instance of the class with the given class name.

example:  
when I have a string like this:

str = “Array”

I want to create a new Array class base on the information in str.

any ideas how this could be done ?

thanks a lot

Markus

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<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 3, 2006, 2:21pm UTC](https://www.ruby-forum.com/t/how-to-create-classes-automatically/101154/2 "2006-08-03T14:21:50Z")

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Object.const\_get(“Array”).new

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<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 3, 2006, 2:21pm UTC](https://www.ruby-forum.com/t/how-to-create-classes-automatically/101154/3 "2006-08-03T14:21:50Z")

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On 8/3/06, removed\_email\_address@domain.invalid [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> I want to create a new Array class base on the information in str.  
> any ideas how this could be done ?

str = “Array”  
Object.const\_get(str).new

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<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 3, 2006, 2:23pm UTC](https://www.ruby-forum.com/t/how-to-create-classes-automatically/101154/4 "2006-08-03T14:23:47Z")

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thank you very much.

Markus