I have two arrays like this:
keys = ['a', 'b', 'c']
values = [1, 2, 3]
Is there a simple way in Ruby to convert those arrays into the following hash?
{ 'a' => 1, 'b' => 2, 'c' => 3 }
Here is my way of doing it, but I feel like there should be a built-in method to easily do this.
def arrays2hash(keys, values)
hash = {}
0.upto(keys.length - 1) do |i|
hash[keys[i]] = values[i]
end
hash
end
The following works in 1.8.7:
keys = ["a", "b", "c"]
values = [1, 2, 3]
zipped = keys.zip(values)
=> [["a", 1], ["b", 2], ["c", 3]]
Hash[zipped]
=> {"a"=>1, "b"=>2, "c"=>3}
This appears not to work in older versions of Ruby (1.8.6). The following should be backwards compatible:
Hash[*keys.zip(values).flatten]
Another way is to use each_with_index:
hash = {}
keys.each_with_index { |key, index| hash[key] = values[index] }
hash # => {"a"=>1, "b"=>2, "c"=>3}
The same can be done using Array#transpose method. If you are using Ruby version >= 2.1, you can take the advantage of the method Array#to_h, otherwise use your old friend, Hash::[]
keys = ['a', 'b', 'c']
values = [1, 2, 3]
[keys, values].transpose.to_h
# => {"a"=>1, "b"=>2, "c"=>3}
Hash[[keys, values].transpose]
# => {"a"=>1, "b"=>2, "c"=>3}
.zip method shown below? e.g. more performant, etc.?Try this, this way the latter one d will overwrite the former one c
irb(main):001:0> hash = Hash[[[1,2,3,3], ['a','b','c','d']].transpose]
=> {1=>"a", 2=>"b", 3=>"d"}
irb(main):002:0>
In current Ruby keys.zip(values).to_h is probably the most readable short solution.
References:
