I have an array of hashes:
[{"sex"=>"male"}, {"sex"=>"male"}, {"sex"=>"female"}]
How can I convert it to array of values:
["male", "male", "female"]
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6 Answers
In this case,
[{"sex"=>"male"}, {"sex"=>"male"}, {"sex"=>"female"}].map(&:values).flatten
should work.
It takes an array from each hash, then flatten the nested array.
Comments
[{"sex"=>"male"}, {"sex"=>"male"}, {"sex"=>"female"}].flat_map(&:values)
Comments
A generic approach to this that would take into account other possible keys:
list = [{"sex"=>"male"}, {"sex"=>"male"}, {"sex"=>"female"}]
# Collect the 'sex' key of each hash item in the list.
sexes = list.collect { |e| e['sex'] }
1 Comment
squiguy
I like this approach in case there are more keys than just the desired one. +1
arr = [{"sex"=>"male"}, {"sex"=>"male"}, {"sex"=>"female"}]
arr.map(&:values).flatten
EDIT: As directed by @tadman. Thanks!
3 Comments
tadman
There's no need to in-place flatten on an intermediate value.
flatten will do the job.
kiddorails
@tadman Right. :) I just considered it, incase AdamNYC wished to retain them in the same array.
tadman
That
flatten! call only affects the result of the map operation, and does not modify arr.You can "map" the elements inside array, take the values of hashes, them "flatten" the resultant array.
[{"sex"=>"male"}, {"sex"=>"male"}, {"sex"=>"female"}].map{|h| h.values }
=> [["male"], ["male"], ["female"]]
[["male"], ["male"], ["female"]].flatten
=> ["male", "male", "female"]
In a single line, you can:
[{"sex"=>"male"}, {"sex"=>"male"}, {"sex"=>"female"}].map{|h| h.values }.flatten
or:
[{"sex"=>"male"}, {"sex"=>"male"}, {"sex"=>"female"}].map(&:values).flatten
Docs:
4 Comments
sawa
-1 for posing an answer 12 minutes after an answer with the same solution was posted.
tadman
It is more thorough, but this exact solution has already been posted three times. Unlike being fashionably late to the party, this is just redundant.
Philip Sampaio
Sorry, I don't knew that it was a race. Should I write lighting fast for earn some points the next time? I was trying to give a good answer, that include search something else. Sorry if I'm not fast enough.
the Tin Man
It's not a race per se, it's a contest to provide the best answer, which is measured in efficiency and clarity, basically coming down the most Ruby-like often. Of course, being first with that helps, but often someone will post much later, with a more thought-out and comprehensive answer, and win the day. Some OPs grab the first answer without any knowledge of what would make the best answer, so you'll see a negative score for the selected answer, and another answer with a very high positive score.
arr = Array.new
my_hash.each do |el|
#collect them here...
arr.push(el["sex"]);
end
Hope it helps
3 Comments
tadman
This doesn't transform, it just prints. You've left out the critical part of this. Not really an answer, is it?
lrl
I did write where he would collect them... so here it is corrected Thank you
tadman
There are several other answers which provide this functionality. This non-answer should be removed.