Ruby hashes

Ruby
1

Is there a way in Ruby to pass a hash value from string (or whatever) to
an Array dinamically?

Example: An array of objects Teacher, each with his name and belonging
school. After iterating though its elements, we want an output of the
type, “school_name_A” => “teacher_name_A”, “school_name_B” =>
[“teacher_name_B”, “teacher_name_C”].

…or maybe there is another simpler way of doing this?

2

Alvaro P. wrote:

Is there a way in Ruby to pass a hash value from string (or whatever) to
an Array dinamically?

Example: An array of objects Teacher, each with his name and belonging
school. After iterating though its elements, we want an output of the
type, “school_name_A” => “teacher_name_A”, “school_name_B” =>
[“teacher_name_B”, “teacher_name_C”].
It’s easier if you allow:

{“school_name_A” => [“teacher_name_A”],
“school_name_B” => [“teacher_name_B”, “teacher_name_C”]}

That way you can do this:

schools = Hash.new{|h,k| h[k] = []}
teachers.each {|teacher| schools[teacher.school] << teacher.name}

3

Alvaro P. wrote:

Example: An array of objects Teacher, each with his name and belonging
school. After iterating though its elements, we want an output of the
type, “school_name_A” => “teacher_name_A”, “school_name_B” =>
[“teacher_name_B”, “teacher_name_C”].

hash = Hash.new {|h,k| h[k] = []}
teachers.each do |teacher|
hash[teacher.school] << teacher.name
end

HTH,
Sebastian

4

Wow, exactly same solution :wink:

but it works! thank you very much to both.