Using "AND" operation to select hashes from array of hashes in ruby

Question

input = [ {"name" => "adam",  "nick" => ["kuruvi", "cali"] },
          {"name" => "eve",   "nick" => ["cali"]           },
          {"name" => "enoch", "nick" => []                 },    
          {"name" => "ebe",   "nick" => ["test", "wrong"]  },
          {"name" => "fred",  "nick" => ["da"]             } ]

I want to select hashes which contains "da" & "cali" in "nick".

input.select do |d|
  d["nick"].include?("cali")
end

gives

[{"name"=>"adam", "nick"=>["kuruvi", "cali"]},
 {"name"=>"eve", "nick"=>["cali"]}]

How can we include two parameters in check. Eg: include?("cali","da") so that my result will be

 [{"name"=>"adam", "nick"=>["kuruvi", "cali"]},
  {"name"=>"eve", "nick"=>["cali"]},
  {"name" => "fred",  "nick" => ["da"]}]

Tried this

 i = ["da","cali"]
 input.select do |d|
   d["nick"].all? { |v| i.include? v }
 end

=> [{"name" => "adam",  "nick" => ["kuruvi", "cali"]},
    {"name" => "eve",   "nick" => ["cali"]},
    {"name" => "enoch", "nick" => []},
    {"name" => "fred",  "nick" => ["da"]}]

(but this returns hashes with "nick"=[] also)

Cary Swoveland · Accepted Answer · 2016-09-08 21:21:13Z

2

On the basis of your desired result you are referring to "or", not "and". The following uses the method Array#&.

input.reject { |h| (h["nick"] & ["cali", "da"]).empty? }
  #=> [{"name"=>"adam", "nick"=>["kuruvi", "cali"]},
  #    {"name"=>"eve", "nick"=>["cali"]},
  #    {"name"=>"fred", "nick"=>["da"]}]

answered Sep 8, 2016 at 21:21

Cary Swoveland

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Comments

tadman · Accepted Answer · 2016-09-08 21:57:02Z

1

You need to do two different include? tests:

l = d['nick']
l.include?('da') && l.include?('cali')

You could also try:

(d['nick'] & %w[ da cali ]).length == 2

Or if you want you could write your own method to test for overlap like that, perhaps even patching it into Array as include_all?

edited Sep 8, 2016 at 21:57

answered Sep 8, 2016 at 20:48

tadman

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3 Comments

user3636388 Over a year ago

Tried this:: i = ["da","cali"] input.select do |d| d["nick"].all? { |v| i.include? v } end

user3636388 Over a year ago

the above returns {"name" => "enoch", "nick" => []} also..where "nick" is []

tadman Over a year ago

The all? call isn't in the right spot there. That won't work.

davidhu · Accepted Answer · 2016-09-08 22:31:22Z

0

Instead of using all?, you can use any? to achieve the desired result.

input.select do |d|
  d["nick"].any? { |h| ['cali','da'].include?(h) }
end

This returns

[{"name"=>"adam", "nick"=>["kuruvi", "cali"]}, 
 {"name"=>"eve",  "nick"=>["cali"]}, 
 {"name"=>"fred", "nick"=>["da"]}]

answered Sep 8, 2016 at 22:31

davidhu

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