How to map ruby hashes correctly based on key provided - ruby-on-rails

Question

My data is like:
h = { themes_data: {
Marketing: [
{
id: 68,
projectno: "15",
}
],
Produktentwicklung: [
{
id: 68,
projectno: "15",
},
{
id: 4,
projectno: "3",
}
],
Marketing_summary: [
{
ges: {
result: "47.6"
},
theme: "Marketing"
}
],
Produktentwicklung_summary: [
{
ges: {
result: "87.7"
},
theme: "Produktentwicklung"
}
]
}
}
And my output should be like:
{ "marketing" => [
{
id: 68,
projectno: "15",
},
{
ges: {
result: "47.6"
},
theme: "Marketing"
}
],
"Produktentwicklung" => [
{
id: 68,
projectno: "15"
},
{
id: 4,
projectno: "3",
},
{
ges: {
result: "87.7"
},
theme: "Produktentwicklung"
}
]
}
Code:
def year_overview_theme
branch_hash = {}
#themes_data.each do |td|
arr = []
td[1].map do |dt|
arr << [{content: dt[:projectno], size: 5, align: :right, background_color: 'D8E5FF'}]
end
branch_hash["#{td[0]}"] = arr
end
branch_hash
end
The problem is that it does not iterate for right hash key.
For example, i want like:
marketing + marketing_summary as 1 hash and similarly
Produktentwicklung = Produktentwicklung_summary as one hash but there is some problem in my logic.
Is there a way that I can check like after 2 iteration,
it should do arr << data with branch_hash["#{td[0]}"] = arr ?

Answer 1

The desired hash can be constructed as follows.
h[:themes_data].each_with_object({}) { |(k,v),g|
g.update(k.to_s[/[^_]+/]=>v) { |_,o,n| o+n } }
#=> { "Marketing"=>[
# {:id=>68, :projectno=>"15"},
# {:ges=>{:result=>"47.6"}, :theme=>"Marketing"}
# ],
# "Produktentwicklung"=>[
# {:id=>68, :projectno=>"15"},
# {:id=>4, :projectno=>"3"},
# {:ges=>{:result=>"87.7"}, :theme=>"Produktentwicklung"}
# ]
# }
This uses the form of Hash#update (aka merge) that employs a block to determine the values of keys that are present in both hashes being merged. Here that block is:
{ |_,o,n| o+n }
The first block variable, _, is the common key. I have represented it with an underscore (a valid local variable) to tell the reader that it is not used in the block calculation. That is common practice. The values of the other two block variables, o and n, are explained at the link for the method update.
The regular expression /[^_]+/, matches one or more characters from the start of the string that are not (^) underscores. When used with the method String#[], we obtain:
"Marketing"[/[^_]+/] #=> "Marketing"
"Marketing_summary"[/[^_]+/] #=> "Marketing"

Answer 2

Let me start with a note: This looks to me like something that should rather be solved in SQL (if it's coming from SQL) instead of Ruby.
With that out of the way, here's a solution that should work:
output = {}
themes_data.each do |theme, projects|
projects.each do |project|
key = project[:theme] || theme.to_s
output[key] ||= [] # make sure the target is initialized
output[key] << project
end
end
There would probably be more elegant solutions using reduce or each_with_object but this works and it's simple enough.

Answer 3

keys = themes_data.keys
summary_keys = themes_data.keys.grep(/_summary/)
result = {}.tap do |hash|
(keys - summary_keys).each do |key|
hash[key] = themes_data[key] + themes_data["#{key}_summary".to_sym]
end
end