I have a hash that currently looks like this:
{
"prefix1_key1": [a, b],
"prefix1_key2": [c, d],
"prefix2_key1": [e, f],
"prefix3_key1": [g, h]
}
And I would want to transfer this into:
{
"prefix1": [a, b, c, d],
"prefix2": [e, f],
"prefix3": [g, h]
}
Is there any clean way that I can do this?
Here is a working solution:
hash = {
"prefix1_key1": [a, b],
"prefix1_key2": [c, d],
"prefix2_key1": [e, f],
"prefix3_key1": [g, h]
}
hash.each_with_object({}) do |ary, result|
key = ary[0].to_s.split('_')[0]
(result[key] ||= []).concat(ary[1])
end
Input
hash = {
"prefix1_key1": ['a', 'b'],
"prefix1_key2": ['c', 'd'],
"prefix2_key1": ['e', 'f'],
"prefix3_key1": ['g', 'h']
}
Code
p hash.group_by { |k, v| k.to_s.split("_").first }
.transform_values { |x| x.flat_map(&:pop) }
Output
{"prefix1"=>["a", "b", "c", "d"], "prefix2"=>["e", "f"], "prefix3"=>["g", "h"]}