# Array to hash **URL:** \ **Category:** Ruby\ **Created:** [March 20, 2007, 12:33pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421 "2007-03-20T12:33:46Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Servando\_G](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@Servando\_G](https://www.ruby-forum.com/u/Servando_G)\ **Post date:** [March 20, 2007, 12:33pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421/1 "2007-03-20T12:33:46Z")
Hello all     Is there a method to collect the items in an array into a hash   I want to go from this X =[1,2,3,4,5,6] to this Y={1 =\>2, 3 =\>4, 5 =\>6}   Just seems like there should be one   Thanks in advance   Sam ---
**Author:** ![Servando\_G](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@Servando\_G](https://www.ruby-forum.com/u/Servando_G)\ **Post date:** [March 20, 2007, 12:43pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421/2 "2007-03-20T12:43:47Z")
Hi – On 3/20/07, Servando G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Hello all > Is there a method to collect the items in an array into a hash > > I want to go from this X =[1,2,3,4,5,6] to this Y={1 =\>2, 3 =\>4, 5 =\>6} Hash[\*X] David ---
**Author:** ![Servando\_G](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@Servando\_G](https://www.ruby-forum.com/u/Servando_G)\ **Post date:** [March 20, 2007, 12:47pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421/3 "2007-03-20T12:47:48Z")
On 3/20/07, Servando G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > Sam > Try this arr = [1,2,3,4,5,6] ahash = Hash[\*arr] p arr p ahash Harry – [http://www.kakueki.com/ruby/list.html](http://www.kakueki.com/ruby/list.html) Japanese Ruby List Subjects in English ---
**Author:** ![Servando\_G](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@Servando\_G](https://www.ruby-forum.com/u/Servando_G)\ **Post date:** [March 20, 2007, 12:53pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421/4 "2007-03-20T12:53:49Z")
David     No Way that is to easy. My new question to you is how does this work. Where can I read the source code for this method \> Hi -- \> \> On 3/20/07, Servando Garcia wrote: \> \>\> Hello all \>\> Is there a method to collect the items in an array into a hash \>\> \>\> I want to go from this X =[1,2,3,4,5,6] to this Y={1 =\>2, 3 =\>4, \>\> 5 =\>6} \>\> \> Hash[\*X] \> \> \> David ---
**Author:** ![Servando\_G](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@Servando\_G](https://www.ruby-forum.com/u/Servando_G)\ **Post date:** [March 20, 2007, 3:29pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421/5 "2007-03-20T15:29:58Z")
On 20 mars 07, at 12:53, Servando G. wrote: > Where can I read the source code for this method ? \<[http://svn.ruby-lang.org/cgi-bin/viewvc.cgi/trunk/hash.c](http://svn.ruby-lang.org/cgi-bin/viewvc.cgi/trunk/hash.c)? revision=11708&view=markup\> The function you are looking for is ‘rb\_hash\_s\_create’. ---
**Author:** ![Servando\_G](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@Servando\_G](https://www.ruby-forum.com/u/Servando_G)\ **Post date:** [March 20, 2007, 3:37pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421/6 "2007-03-20T15:37:20Z")
Hi – On 3/20/07, Servando G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > David > No Way that is to easy. My new question to you is how does this work. The ‘unarray’ operator \* turns an array into a list. So in effect you’re doing: Hash[1,2,3,4,5,6] David ---
**Author:** ![Servando\_G](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@Servando\_G](https://www.ruby-forum.com/u/Servando_G)\ **Post date:** [March 20, 2007, 12:51pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421/7 "2007-03-20T12:51:48Z")
Guess I should have googled harder/longer I have found some code that appears to work. Now I'll have to spend sometime stepping through it. Here is the code:   class Array def to\_h(&block) Hash[\*self.collect { |v| [v, block.call(v)] }.flatten] end end     and the link to the page: [http://snippets.dzone.com/posts/show/302](http://snippets.dzone.com/posts/show/302)   Harold, Please forgive my impatience   Sam \> Hello all \>   Is there a method to collect the items in an array into a hash \> \> I want to go from this X =[1,2,3,4,5,6] to this Y={1 =\>2, 3 =\>4, 5 \> =\>6} \> \> Just seems like there should be one \> \> Thanks in advance \> \> Sam ---
**Author:** ![Servando\_G](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@Servando\_G](https://www.ruby-forum.com/u/Servando_G)\ **Post date:** [March 20, 2007, 9:32pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421/8 "2007-03-20T21:32:43Z")
On Tue, Mar 20, 2007 at 08:33:09PM +0900, Servando G. wrote: > I want to go from this X =[1,2,3,4,5,6] to this Y={1 =\>2, 3 =\>4, 5 =\>6} > >   > > Just seems like there should be one > >   > > Thanks in advance > >   > > Sam I’m glad you got the answer you were seeking. I have a request, though: Please provide plain text email content in the future. Some of us (intentionally) avoid HTML email. ---
**Author:** ![Servando\_G](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/ad7895/32.png) [@Servando\_G](https://www.ruby-forum.com/u/Servando_G)\ **Post date:** [March 20, 2007, 3:40pm UTC](https://www.ruby-forum.com/t/array-to-hash/89421/9 "2007-03-20T15:40:21Z")
On 3/20/07, Servando G. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > David > No Way that is to easy. My new question to you is how does this work. > Where can I read the source code for this method It’s a combination of two things: 1. Hash.[] creates a hash from a comma separated even-length list Hash[1,2,3,4,5,6] # =\> { 1=\>2, 3=\>4, 5=\>6 } 1. \*ary converts an array into a comma-separated list def foo(a, b=nil, c=nil) p a p b p c end ary = [1,2,3] def foo(a, b=nil, c=nil) p a p b p c end ary = [1,2,3] irb\> foo(ary) [1, 2, 3] nil nil =\> nil irb\> foo(\*ary) 1 2 3 =\> nil martin