How get value from array of strings in Ruby 2.0

Question

I have this array of strings:

array = [ "nike air", "nike steam","nike softy" ,"nike strength",
          "smooth sleeper","adidas air","addidas jogar","adidas softy","adidas heels"]

I want to extract strings from this as SQL like query.

E.g if user enter word "nike". Then 4 strings should be return as result

           "nike air", "nike steam","nike softy" ,"nike strength"

E.g if user enter word "adidas". Then 4 strings should be return as result

           "adidas air","addidas jogar","adidas softy","adidas heels"

Is it possible?

What code have you written to solve the problem? This is a pretty simple thing to do. — the Tin Man
– the Tin Man, Commented Jun 3, 2013 at 14:47
Not directly related but possibly relevant: SQL has a LIKE predicate, which allows you to pretty much do this but at the database layer. It might offer you a more flexible solution. — Matheus Moreira
– Matheus Moreira, Commented Jun 3, 2013 at 16:10

Marek Lipka · Accepted Answer · 2013-11-05 09:07:58Z

8

array.grep(query)

Returns the array subset that matches the query.

edited Nov 5, 2013 at 9:07

answered Jun 3, 2013 at 14:47

Marek Lipka

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3 Comments

Muhammad Kashif Ali Over a year ago

array.grep('nike') gives be blank array

Marek Lipka Over a year ago

Try with Regexp instead of String.

Stefan Over a year ago

@Kashiftufail i.e. /nike/ instead of 'nike'

Phrogz · Accepted Answer · 2013-06-03 18:30:23Z

7

Use Enumerable#grep:

matches = array.grep /nike/

Add /i for case insensitive. To construct a regexp from a string:

re = Regexp.new( Regexp.escape(my_str), "i" )

Or, if you want your users to be able to use special Regexp queries, just:

matches = array.grep /#{my_str}/

edited Jun 3, 2013 at 18:30

answered Jun 3, 2013 at 14:48

Phrogz

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2 Comments

Muhammad Kashif Ali Over a year ago

@Phrogh matches = array.grep /nike/ give me accurate result but matches = array.grep /"nike"/ give me nothing. so how i should execute this code in my controller matches = array.grep /"#{params[:term]}"/ while params[:term] is string value

Stefan Over a year ago

Use array.grep(Regexp.new(Regexp.escape(params[:term])))

Boris Stitnicky · Accepted Answer · 2013-06-03 14:54:19Z

2

Or you can build your query method by yourself:

def func( array )
  array.each_with_object [] do |string, return_array|
    return_array << string if string =~ /nike/
  end
end

edited Jun 3, 2013 at 14:54

Boris Stitnicky

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answered Jun 3, 2013 at 14:49

sethi

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2 Comments

Phrogz Over a year ago

Way more work (for both programmer and computer) than is necessary.

Dave Newton Over a year ago

@Phrogz Definitely for programmer--is the implementation of grep C-ish? Otherwise wouldn't grep do much the same thing? I can't check at the moment.

Arup Rakshit · Accepted Answer · 2013-06-03 15:12:32Z

2

array = [ "nike air", "nike steam","nike softy" ,"nike strength",
          "smooth sleeper","adidas air","addidas jogar","adidas softy","adidas heels"]
array.select{|i| i.include? "nike"}

# >> ["nike air", "nike steam", "nike softy", "nike strength"]

answered Jun 3, 2013 at 15:12

Arup Rakshit

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2 Comments

Daryl Gill Over a year ago

@louism Perhaps you should explain your answer on the changes and how this approach is the "best" to resolve the OPS problem

user2398029 Over a year ago

This method is clearer. "Select the words that contain 'nike'" is simple, elegant and more idiomatic Ruby IMHO.

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