Ruby parsing Array (Special Case) - ruby-on-rails

Question

I am executing a query and getting the following data from the database in an array (MySql2 type object):
+-----------+---------------+---------------+------+------+---------------+
| build | platform_type | category_name | pass | fail | indeterminate |
+-----------+---------------+---------------+------+------+---------------+
| 10.0.1.50 | 8k | UMTS | 10 | 2 | 5 |
| 10.0.1.50 | 8k | UMTS | 10 | 2 | 5 |
| 10.0.1.50 | 8k | IP | 10 | 2 | 5 |
| 10.0.1.50 | 8k | IP | 14 | 1 | 3 |
| 10.0.1.50 | 9k | IP | 14 | 1 | 3 |
| 10.0.1.50 | 9k | IP | 12 | 1 | 1 |
| 10.0.1.50 | 9k | UMTS | 12 | 1 | 1 |
| 10.0.1.50 | 9k | UMTS | 12 | 1 | 1 |
| 10.0.1.50 | 9k | UMTS | 12 | 1 | 1 |
| 10.0.1.50 | 9k | Stability | 9 | 4 | 0 |
| 10.0.1.50 | 9k | Stability | 15 | 1 | 0 |
I want to display it on my UI in a table, something like this :
+-----------+---------------+---------------+------+------+---------------+
| build | platform_type | category_name | pass | fail | indeterminate |
+-----------+---------------+---------------+------+------+---------------+
| | | UMTS | 20 | 4 | 10 |
| | 8k |---------------------------------------------|
| | | IP | 24 | 3 | 8 |
| |---------------|---------------------------------------------|
| 10.0.1.50 | | IP | 26 | 2 | 4 |
| | |---------------------------------------------|
| | 9k | UMTS | 36 | 3 | 3 |
| | |---------------------------------------------|
| | | Stability | 24 | 5 | 0 |
---------------------------------------------------------------------------
I did try using hash to find unique platform types for the build. But as I am very new to ruby, I am having trouble using the hash properly. I would appreciate if someone can help me parse the data.

Answer 1

Assuming you have an array of arrays:
#data = sql_results.group_by(&:first).map do |b, bl|   
[b, bl.group_by(&:second).map{|p, pl| [p, pl.map{|r| r[2..-1]}] }.sort_by(&:first)]
end.sort_by(&:first)
Here is how to break down the logic.
group the rows by first column. This will return a hash with key as the first column name and value as an array of rows.
group each build list by 2nd column(platform type). Each group should contain the array of col values from 3 to the last col.
sort the platform lists by platform type
sort the build lists by build name
The resultant structure would like this:
[
[
"10.0.1.50", [
[
"8k", [
["UMTS", 20, 4, 10],
["IP", 24, 3, 8]
]
],
[
"9k", [
["IP", 26, 2, 4],
["UMTS", 36, 3, 3],
["UMTS", 24, 5, 0]
]
]
]
]
]
You can use this in your view layout example:
%table
%tr
- %w(build platform_type category_name pass fail indeterminate).each do |name|
%th=name
- #data.each do |build, build_list|
%tr
%td=build
%td{:colspan=4}
%table
- build_list.each do |build, platform_list|
%tr
%td=build
%td{:colspan=3}
%table
- platform_list.each do |row|
%tr
- row.each do |attr|
%td=attr
If you use an AR model here is what you do:
class Build < ActiveRecord::Base
def self.builds_by_platform
reply = Hash.new{|h, k| h[k] = Hash.new{|h, k| h[k] = []}}
Build.order("build ASC, platform_type ASC").find_each do |row|
reply[row.build][row.platform_type] << row
end
reply.map{|b, bh| [b, bh.sort_by(&:first)}.sort_by(&:first)
end
end
In your controller you can access the normalized variable as:
#report _list = Build.builds_by_platform
You can use the #report _list variable for rendering the table.