Question

I have a Ruby 2D Array, where each array has a row from a SQL query and its columns inside the subarray.

@mastertest = connection.execute("select code_ver from mastertest")

which might contain something like this:

@mastertest = [{"abc"} , {"abc"}, {"pqr"}, {"xyz"}, {"pqr"}, {"pqr"}]

Now, I want to form another 2D array which would give me just the rows which have a unique value of code_ver with their count.

Something like this:

@result = [{"abc", 2} , {"xyz", 1} , {"pqr", 3}]

Answer 1

@result = @mastertest.inject(Hash.new(0)) { |hash,element|
  hash[element] +=1
  hash
}