# Multidimensional ".index"?

**URL:** <https://www.ruby-forum.com/t/multidimensional-index/64216>\
**Category:** Ruby\
**Created:** [June 23, 2006, 4:27am UTC](https://www.ruby-forum.com/t/multidimensional-index/64216 "2006-06-23T04:27:03Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Meino\_Christian\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/7993a0/32.png) [@Meino\_Christian\_C](https://www.ruby-forum.com/u/Meino_Christian_C)\
**Post date:** [June 23, 2006, 4:27am UTC](https://www.ruby-forum.com/t/multidimensional-index/64216/1 "2006-06-23T04:27:03Z")

</div>

Hi,

a=[1,2,3,4]  
a.index(3) -\> 2

Is there any way to do such things:

a=[[1,2,3,4],[5,6,7,8],[9,10,11,12]]

a.index(6) -\> [1,1]

may be for n-dimensional arrays, too ?

Thank you very much for any helpful reply in advance !

Keep ruby!  
mcc

---

<div class="post-metadata">

**Author:** ![Meino\_Christian\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/7993a0/32.png) [@Meino\_Christian\_C](https://www.ruby-forum.com/u/Meino_Christian_C)\
**Post date:** [June 23, 2006, 4:46am UTC](https://www.ruby-forum.com/t/multidimensional-index/64216/2 "2006-06-23T04:46:48Z")

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From: removed\_email\_address@domain.invalid  
Subject: Re: Multidimensional “.index” ?  
Date: Fri, 23 Jun 2006 11:35:10 +0900

> > 
> 
> harp:~ \> cat a.rb  
> p na[idx]
> 
> ```
> [0, 0, 0, 1] ]
> 
> ```
> 
> and so much more. it’s all on rubyforge.
> 
> ## -a
> 
> suffering increases your inner strength. also, the wishing for suffering  
> makes the suffering disappear.
> 
> - h.h. the 14th dali lama

THANK YOU! :))

Have a nice weekend!  
mcc

---

<div class="post-metadata">

**Author:** ![Meino\_Christian\_C](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/7993a0/32.png) [@Meino\_Christian\_C](https://www.ruby-forum.com/u/Meino_Christian_C)\
**Post date:** [June 23, 2006, 4:37am UTC](https://www.ruby-forum.com/t/multidimensional-index/64216/3 "2006-06-23T04:37:12Z")

</div>

On Fri, 23 Jun 2006, Meino Christian C. wrote:

> may be for n-dimensional arrays, too ?
> 
> Thank you very much for any helpful reply in advance !
> 
> Keep ruby!  
> mcc

harp:~ \> cat a.rb  
require ‘narray’

na = NArray.to\_na [  
[1,2,3,4],  
[5,6,7,8],  
[9,10,11,12]  
]

idx = na.eq 7  
p idx  
p na[idx]

idx = na.eq(7).or(na.eq(12))  
p idx  
p na[idx]

idx = na.gt 6  
p idx  
p na[idx]

harp:~ \> ruby a.rb  
NArray.byte(4,3):  
[[ 0, 0, 0, 0],  
[0, 0, 1, 0],  
[0, 0, 0, 0] ]  
NArray.int(1):  
[7]  
NArray.byte(4,3):  
[[ 0, 0, 0, 0],  
[0, 0, 1, 0],  
[0, 0, 0, 1] ]  
NArray.int(2):  
[7, 12]  
NArray.byte(4,3):  
[[ 0, 0, 0, 0],  
[0, 0, 1, 1],  
[1, 1, 1, 1] ]  
NArray.int(6):  
[7, 8, 9, 10, 11, 12]

and so much more. it’s all on rubyforge.

-a