How do I create an array from columns?

Question

How do I create an array from database columns?

My table Reklamer:

id  virksomhed  dato                   klik     
10  Iqmedier    2011-02-15 00:00:00     4   
11  Iqmedier    2011-02-15 00:00:00     2   
12  Iqmedier    2011-02-15 00:00:00     3

I want to create an array of all the columns klik. Like [4, 2, 3]

An can someone explain what a block and an object is :) Or where I can read something about it.

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Dogbert · Accepted Answer · 2011-02-16 21:05:05Z

1

I'm guessing you have a model named Reklamer too.

You can do the following to get the array

Reklamer.select('klik').all.map(&:klik)

Edit:

(Array.map in Ruby) map(&:klik) is just a shorthand for

.map do |record|
  record.klik
end

It returns the value of klik for each record, and creates a new array using those values.

edited Feb 16, 2011 at 21:05

answered Feb 16, 2011 at 20:57

Dogbert

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3 Comments

Rails beginner Over a year ago

What does .map(&:klik)? Does it create an array?

Rails beginner Over a year ago

How do i only create an array of those were the column Virksomhed = Iqmedier. I have tried with this data: <%= Reklamer.select(:all, :conditions => {:virksomhed => 'Iqmedier'}).select('earn').all.map(&:earn) %> But gets a error: wrong number of arguments (2 for 1)

Dogbert Over a year ago

Try Reklamer.where(:virksomhed => 'Iqmedier').all.map(&:earn)

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