map array with condition

Question

I have array like

 strings = ["by_product[]=1", "by_product[]=2", "page=1", "per_page=10", "select[]=current", "select[]=requested", "select[]=original"]

which is array of params from request

Then there is code that generates hash from array

arrays = strings.map do |segment|
        k,v = segment.split("=")
        [k, v && CGI.unescape(v)]
Hash[arrays]

CUrrent output -

"by_product[]": "2",
      "page":"1",
      "per_page":"10",
      "select[]":"original"

Expected output -

"by_product[]":"1, 2",
      "page":"1",
      "per_page":"10",
      "select[]":"current, requested, original"

The problem is - after split method there are few by_product[] and the last one just overrides any other params, so in result instead of hash with array as value of these params im getting only last one. And i'm not sure how to fix it. Any ideas? Or at least algorithms

added more information

Avdept
– Avdept

2014-07-10 09:16:51 +00:00
Commented Jul 10, 2014 at 9:16 — Avdept
– Avdept, Commented Jul 10, 2014 at 9:16
That's not valid Ruby.. Is it a Hash or Array ?

Arup Rakshit
– Arup Rakshit

2014-07-10 09:17:35 +00:00
Commented Jul 10, 2014 at 9:17 — Arup Rakshit
– Arup Rakshit, Commented Jul 10, 2014 at 9:17
Made it look like a hash, to simplify

Avdept
– Avdept

2014-07-10 09:19:26 +00:00
Commented Jul 10, 2014 at 9:19 — Avdept
– Avdept, Commented Jul 10, 2014 at 9:19
What is strings value?

user2503775
– user2503775

2014-07-10 09:20:25 +00:00
Commented Jul 10, 2014 at 9:20 — user2503775
– user2503775, Commented Jul 10, 2014 at 9:20

Pavel S · Accepted Answer · 2014-07-10 09:45:04Z

3

So try this:

hash = {}
arrays = strings.map do |segment|
          k,v = segment.split("=")
          hash[k]||=[]
          hash[k] << v
        end

output is

1.9.3-p547 :025 >   hash
 => {"by_product[]"=>["1", "2"], "page"=>["1"], "per_page"=>["10"], "select[]"=>["current", "requested", "original"]}

or if you want just strings do

arrays = strings.map do |segment|
          k,v = segment.split("=")
          hash[k].nil? ? hash[k] = v : hash[k] << ", " + v
        end

edited Jul 10, 2014 at 9:45

answered Jul 10, 2014 at 9:28

Pavel S

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4 Comments

Avdept Over a year ago

will try, and give feedback

j-dexx Over a year ago

Assuming the comma's are important in the output I would change both the hash lines on the second one to hash[k].nil? ? hash[k] = v : hash[k] << ", " + v personally

Pavel S Over a year ago

Yes, you are right.@Avdept, consider @Baloo's comment

Avdept Over a year ago

@pavelS i had to change your code a little bit, so params that have no array, would be like a string and with array would be array-like

Stefan · Accepted Answer · 2014-07-10 12:03:58Z

Don't reinvent the wheel, CGI and Rack can already handle query strings.

Assuming your strings array comes from a single query string:

query = "by_product[]=1&by_product[]=2&page=1&per_page=10&select[]=current&select[]=requested&select[]=original"

you can use CGI::parse: (all values as arrays)

require 'cgi'

CGI.parse(query)
#=> {"by_product[]"=>["1", "2"], "page"=>["1"], "per_page"=>["10"], "select[]"=>["current", "requested", "original"]}

or Rack::Utils.parse_query: (arrays where needed)

require 'rack'

Rack::Utils.parse_nested_query(query)
# => {"by_product[]"=>["1", "2"], "page"=>"1", "per_page"=>"10", "select[]"=>["current", "requested", "original"]}

or Rack::Utils.parse_nested_query: (values without [] suffix)

require 'rack'

Rack::Utils.parse_nested_query(query)
# => {"by_product"=>["1", "2"], "page"=>"1", "per_page"=>"10", "select"=>["current", "requested", "original"]}

And if these are parameters for a Rails controller, you can just use params.

raviture · Accepted Answer · 2014-07-10 14:40:41Z

1

this will also work :

strings.inject({}){ |hash, string| 
  key, value = string.split('='); 
  hash[key] = (hash[key]|| []) << value;
  hash;
}

output : {"by_product[]"=>["1", "2"], "page"=>["1"], "per_page"=>["10"], "select[]"=>["current", "requested", "original"]}

answered Jul 10, 2014 at 14:40

raviture

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Comments

Sk. Irfan · Accepted Answer · 2017-07-12 20:03:22Z

0

As simple as that

array.map { |record| record*3 if condition }

record*3 is the resultant operation you wanna do to the array while mapping

answered Jul 12, 2017 at 20:03

Sk. Irfan

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