With my array of hashes:
data = [{:bool => true, :val => 5}, {:bool => false, :val => 9}, {:bool => true, :val => 1}]
I would like to iterate through the data and retrieve an array of values only. I can do:
data.map{|x| x[:val] if x[:bool]}
which returns:
[5, nil, 1]
But this method requires an additional .compact call to get rid of the nil values.
Is there a better way of achieving this?
Use chaining instead to first select only those where :bool is true, then map the results to :val:
data.select { |h| h[:bool] }.map { |h| h[:val] } #=> [5, 1]
data.map { |x| x[:val] if x[:bool] }.compact is probably the easiest to read, but you can go down to one function call via reduce:
data.reduce([]) { |m,x| m << x[:val] if x[:bool]; m }
It does not seem an elegant way but you can try this:
data = [{:bool => true, :val => 5}, {:bool => false, :val => 9}, {:bool => true, :val => 1}]
result = Array.new
data.each do |b|
val = Hash.try_convert(b)[:val]
result.unshift(val)
end
selectand notcollect?