Accessing data in an array inside Ruby

Question

I'm having trouble accessing data in a "each" statement in Ruby. I'm grabbing data from an SQL query,

mysql> select * from mantis_bug_relationship_table WHERE relationship_type = 2 AND destination_bug_id = 753;
+-----+---------------+--------------------+-------------------+
| id  | source_bug_id | destination_bug_id | relationship_type |
+-----+---------------+--------------------+-------------------+
| 103 |           765 |                753 |                 2 |
+-----+---------------+--------------------+-------------------+

Then I add each of the results to an array like so that have a relationship_type of 2,

parent_map = {}
current = 1

# for each loop is here that populates parent_map

parent_map[current] = { issues_map[relation.destination_bug_id] => issues_map[relation.source_bug_id] }
current += 1

# for each loop is here that populates parent_map

Then I try to read data from the parent_map as follows:

parent_map.each do |child, parent|
    pp parent_map   
    print "child: #{child}\n"
    print "parent: #{parent}\n"
    print "---------------------------------------\n"
    STDOUT.flush
  end

This outputs as follows:

{1=>{753=>765}}
child: 1
parent: 753765

The output should be:

child: 753
parent: 765

How am I supposed to access the child and parent?

Answer 1

You are actually dealing with hashes in your example, not arrays.

array = []
hash = {}

In your parent_map.each loop you are grabbing the key and value. Your key is populated by the current variable in your initial population loop, while your value is also a hash containing the parent and child you want to access.

Assuming you want the hash that is your value, you need a sub loop, ala:

parent_map.each do |key, val| # This val is your hash: {753=>765}
  val.each do |child, parent|
    puts "child: #{child}" # 753
    puts "parent: #{parent}" # 765
  end
end

Answer 2

You do not need nested loops as in other answers. Take the second parameter and decompose it.

parent_map.each do |_, (child, parent)|
  pp parent_map
  puts "child: #{child}"
  puts "parent: #{parent}"
  puts "---------------------------------------"
  STDOUT.flush
end

Answer 3

parent_map.each do |current, issues_hash|
  issues_hash.each do |key, value|
    print "child: #{key}\n"
    print "parent: #{value}\n"
  end
end

This should work.