Array to hash

ruby-talk
1

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

2

Hi --

···

On 3/20/07, Servando Garcia <garcia.servando@gmail.com> 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

--
Q. What is THE Ruby book for Rails developers?
A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black\)
   (See what readers are saying! http://www.rubypal.com/r4rrevs.pdf\)
Q. Where can I get Ruby/Rails on-site training, consulting, coaching?
A. Ruby Power and Light, LLC (http://www.rubypal.com)

3

Try this

arr = [1,2,3,4,5,6]
ahash = Hash[*arr]
p arr
p ahash

Harry

···

On 3/20/07, Servando Garcia <garcia.servando@gmail.com> 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}

Just seems like there should be one

Thanks in advance

Sam

--

Japanese Ruby List Subjects in English

4

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

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

5

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.

···

On Tue, Mar 20, 2007 at 08:33:09PM +0900, Servando Garcia wrote:

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<div><SPAN style="font-family:'Arial';font-size:10pt;">&nbsp; &nbsp; Is there a method to collect the items in an array into a hash</SPAN></div>
<div>&nbsp;</div>
<div><SPAN style="font-family:'Arial';font-size:10pt;">I want to go from this X =[1,2,3,4,5,6] to this Y={1 =&gt;2, 3 =&gt;4, 5 =&gt;6}</SPAN></div>
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<div><SPAN style="font-family:'Arial';font-size:10pt;">Just seems like there should be one</SPAN></div>
<div>&nbsp;</div>
<div><SPAN style="font-family:'Arial';font-size:10pt;">Thanks in advance</SPAN></div>
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--
CCD CopyWrite Chad Perrin [ http://ccd.apotheon.org ]
unix virus: If you're using a unixlike OS, please forward
this to 20 others and erase your system partition.

6

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

7

<http://svn.ruby-lang.org/cgi-bin/viewvc.cgi/trunk/hash.c?revision=11708&view=markup&gt;

The function you are looking for is 'rb_hash_s_create'.

···

On 20 mars 07, at 12:53, Servando Garcia wrote:

Where can I read the source code for this method ?

--
Luc Heinrich - luc@honk-honk.com - http://www.honk-honk.com

8

Hi --

···

On 3/20/07, Servando Garcia <garcia.servando@gmail.com> 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

--
Q. What is THE Ruby book for Rails developers?
A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black\)
   (See what readers are saying! http://www.rubypal.com/r4rrevs.pdf\)
Q. Where can I get Ruby/Rails on-site training, consulting, coaching?
A. Ruby Power and Light, LLC (http://www.rubypal.com)

9

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 }

2. *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]

foo(ary)

[1, 2, 3]
nil
=> nil

foo(*ary)

1
2
3
=> nil

martin

···

On 3/20/07, Servando Garcia <garcia.servando@gmail.com> wrote: