Ruby Loop Array and Create Hash for Each Array Object

Question

I'd like to loop through an array and create a hash for each object in the array, then group all those hashes into an array of hashes.

Here's an example starting array for me:

urls = ["http://stackoverflow.com", "http://example.com", "http://foobar.com"]

Now let's say I'd like to have a hash for each of those URLs into an array like this:

urls =[ { 
'url' => "http://stackoverflow.com",
'dns_status' => "200",
'title' => "Stack Overflow"
},
{
'url' => "http://example.com",
'dns_status'=> "200",
'title' => "Example"
}
]

Leaving aside where I get the values for the dns_status and title keys in the example, I guess what I'm missing is how to loop through the original array and create a hash for each object...

I've played around with inject, collect, map and each and read through the docs but can't quite make sense of it or get anything to work.

Any recommendation? Will this be easier to accomplish with a class?

EDIT:

Thanks for your help everyone. Figured this out and got it working. Cheers!

Can you clarify the question? I am a bit confused at present. I understand you have an array (called urls), but what do you want to achieve? You wish to turn the array into an array of hashes instead? — shevy
– shevy, Commented Jul 16, 2014 at 16:17
Yes. I want to create a hash for each url in the array. The hash will have keys like :url and some other values which i'll be doing api lookups on later in the real script — KD100
– KD100, Commented Jul 16, 2014 at 16:26

steenslag · Accepted Answer · 2014-07-16 16:32:21Z

4

Do something with each element of something enumerable and store the result in an array: that is what map does. Specify what you want in the block, like this:

urls = ["http://stackoverflow.com", "http://example.com", "http://foobar.com"]
p res = urls.map{|url| {"url"=>url, "dns_status"=>200, "title"=>url[7..-5]} }

#=> [{"url"=>"http://stackoverflow.com", "dns_status"=>200, "title"=>"stackoverflow"}, {"url"=>"http://example.com", "dns_status"=>200, "title"=>"example"}, {"url"=>"http://foobar.com", "dns_status"=>200, "title"=>"foobar"}]

answered Jul 16, 2014 at 16:32

steenslag

80.2k16 gold badges144 silver badges174 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

KD100 Over a year ago

Perfect. Exactly what I was looking for. Works.

Cary Swoveland Over a year ago

Come on, steen, no horizontal scrolling, please.

shevy · Accepted Answer · 2014-07-16 16:19:46Z

0

"what I'm missing is how to loop through the original array and create a hash for each object..."

urls = [
  "http://stackoverflow.com",
  "http://example.com",
  "http://foobar.com"
]
urls.each {|entry|
  puts entry
}

You could use .map! for instance. But I am still not sure what your target result ought to be. How about this?

urls.map! {|entry|
  { 'url' => entry, 'dns_status' => "200", 'title' => "Stack Overflow"}
}
urls # => [{"url"=>"http://stackoverflow.com", "dns_status"=>"200", "title"=>"Stack Overflow"}, {"url"=>"http://example.com", "dns_status"=>"200", "title"=>"Stack Overflow"}, {"url"=>"http://foobar.com", "dns_status"=>"200", "title"=>"Stack Overflow"}]

Yikes, the result is hard to see. It is this:

[
{
  "url"=>"http://stackoverflow.com",
  "dns_status"=>"200",
  "title"=>"Stack Overflow"
},
{
  "url"=>"http://example.com",
  "dns_status"=>"200",
  "title"=>"Stack Overflow"
},
{
  "url"=>"http://foobar.com",
  "dns_status"=>"200",
  "title"=>"Stack Overflow"
}
]

Obviously, you need to still supply the proper content for title, but you did not give this in your original question so I could not fill it in.

answered Jul 16, 2014 at 16:19

shevy

1,0302 gold badges13 silver badges19 bronze badges

2 Comments

Uri Agassi Over a year ago

why map! and not map?

Cary Swoveland Over a year ago

Not only does map! destroy the original array, but @steenslag has already offered a solution that uses map. The addition of the bang is questionable justification for a separate answer. Moreover, "Stack Overflow" is not the value of title for all elements.

Collectives™ on Stack Overflow

Ruby Loop Array and Create Hash for Each Array Object

2 Answers 2

2 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related