Convert multi-dimensional array format in Ruby/Rails

Question

I have the following code below.

Group.all.collect {|group| [ group.name, group.id ]}.inspect

And this one outputs below.

[["Bankruptcy Group", 1], ["PIA Group", 2], ["Liquidation Group", 3]]

I want to convert to a different format like below.

{"Bankruptcy Group" => 1, "PIA Group"=> 2, "Liquidation Group"=> 3}

How do I do this?

Are you using Ruby on Rails? There might be ActiveRecord methods that can be used to return model ids and names directly from the database using SQL. — user456814
– user456814, Commented Mar 20, 2014 at 7:05
Yes I do. Hence for the original code at the beginning of the sentence. I am still RoR newbie so I don't know a lot of ActiveRecord's API that I can fully muster it... — awongCM
– awongCM, Commented Mar 20, 2014 at 12:25

sawa · Accepted Answer · 2014-03-20 06:17:01Z

3

[["Bankruptcy Group", 1], ["PIA Group", 2], ["Liquidation Group", 3]].to_h

answered Mar 20, 2014 at 6:17

sawa

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1 Comment

Arup Rakshit Over a year ago

I like this one.. simple and in one go.. +1

xdazz · Accepted Answer · 2014-03-20 06:24:13Z

2

You could create the hash directly:

Group.all.inject({}) { |h, g| h[g.name] = g.id; h }

answered Mar 20, 2014 at 6:24

xdazz

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1 Comment

awongCM Over a year ago

Thanks xdazz. I like this one better. Save me lines of code to write them out. Thanks Heaps!

Koraktor · Accepted Answer · 2014-03-20 06:16:09Z

0

array = Group.all.collect { |group| [ group.name, group.id ] }
hash = Hash[array]

answered Mar 20, 2014 at 6:16

Koraktor

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Comments

user456814 · Accepted Answer · 2014-03-20 07:23:51Z

0

The to_h method of Enumerable can be used to convert enumerable objects to hashes when each item in the object can be interpreted as an array of the form [key, value]:

Group.all.map { |g| [g.name, g.id] }.to_h

From the documentation for to_h:

Returns the result of interpreting enum as a list of [key, value] pairs.

answered Mar 20, 2014 at 7:23

user456814

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