Ruby Array to Hash (a better way?)

ruby-talk
1

Hey Guys,

I want to convert an array like the following to a hash. Below is my
current code (I am assuming there is a better way).

Thanks

["foo", "bar", "foo1", "bar1","foo2", "bar2"] convert to
{"foo"=>"bar", "foo1"=>"bar1","foo2"=>"bar2"}

My Current Code:

def array_to_hash(array)
  count = 0
  hash = Hash.new
  (array.length / 2).times do
    hash[array[count]] = array[count+1]
    count += 2
  end
  return hash
end

2

Hey Guys,

I want to convert an array like the following to a hash. Below is my
current code (I am assuming there is a better way).

Thanks

["foo", "bar", "foo1", "bar1","foo2", "bar2"] convert to
{"foo"=>"bar", "foo1"=>"bar1","foo2"=>"bar2"}

Use Hash#

Hash["foo", "bar", "foo1", "bar1","foo2", "bar2"]

=> {"foo1"=>"bar1", "foo2"=>"bar2", "foo"=>"bar"}

hth

Gordon

···

On Aug 1, 12:26 pm, skibud2 <mike.hallo...@gmail.com> wrote:

3

skibud2 pisze:

Hey Guys,

I want to convert an array like the following to a hash. Below is my
current code (I am assuming there is a better way).

Thanks

["foo", "bar", "foo1", "bar1","foo2", "bar2"] convert to
{"foo"=>"bar", "foo1"=>"bar1","foo2"=>"bar2"}

given:
a = ["foo", "bar", "foo1", "bar1","foo2", "bar2"]

puts Hash[*a]

or:

require 'enumerator'
h = {}
a.each_slice(2){|k,v|h[k]=v}
puts h

lopex

4

I've been using Ruby for awhile, and I'm afraid I've never used the *
notation...

I can see that Hash[a] wouldn't work, and that Hash[*a] expands the
array out so that Hash can use it elegantly.

But what, in a general, does the * do?

Or is it just for special cases like this?

Thanks,
    Kyle

5

If you are using Enumerator anyway you can as well do

irb(main):001:0> a = ["foo", "bar", "foo1", "bar1","foo2", "bar2"]
=> ["foo", "bar", "foo1", "bar1", "foo2", "bar2"]
irb(main):002:0> a.to_enum(:each_slice, 2).inject({}) {|h,(k,v)| h[k]=v; h}
=> {"foo1"=>"bar1", "foo2"=>"bar2", "foo"=>"bar"}
irb(main):003:0>

Kind regards

  robert

···

On 01.08.2007 19:34, Marcin Mielżyński wrote:

skibud2 pisze:

Hey Guys,

I want to convert an array like the following to a hash. Below is my
current code (I am assuming there is a better way).

Thanks

["foo", "bar", "foo1", "bar1","foo2", "bar2"] convert to
{"foo"=>"bar", "foo1"=>"bar1","foo2"=>"bar2"}

given:
a = ["foo", "bar", "foo1", "bar1","foo2", "bar2"]

puts Hash[*a]

or:

require 'enumerator'
h = {}
a.each_slice(2){|k,v|h[k]=v}
puts h

6

Kyle Schmitt wrote:

But what, in a general, does the * do?

It turns an array into a list of parameters (or, if used in a method
definition, a list of parameters into an array).

HTH,
Sebastian

···

--
NP: Dream Theater - Only A Matter Of Time
Ist so, weil ist so
Bleibt so, weil war so

7

Hi --

···

On Thu, 2 Aug 2007, Kyle Schmitt wrote:

I've been using Ruby for awhile, and I'm afraid I've never used the *
notation...

I can see that Hash[a] wouldn't work, and that Hash[*a] expands the
array out so that Hash can use it elegantly.

But what, in a general, does the * do?

Or is it just for special cases like this?

It "un-arrays" its operand; in other words, given an array, the *
gives you a list.

David

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