Ersetzen Hash-Wert

Question

ich ein Array von Hashes haben:

[{"__content__"=>"Guitars", "id"=>"2"}, 
{"__content__"=>"For Guitars", "id"=>"3", "parentId"=>"2"}, 
{"__content__"=>"6-string", "id"=>"24", "parentId"=>"2"}, 
{"__content__"=>"7-string", "id"=>"25", "parentId"=>"2"}, 
{"__content__"=>"8-string", "id"=>"26", "parentId"=>"2"}] 

ich die parentId Werte mit den __content__ Werte ersetzen wollen zu bekommen:

[{"__content__"=>"Guitars", "id"=>"2"}, 
{"__content__"=>"For Guitars", "id"=>"3", "parentId"=>"Guitars"}, 
{"__content__"=>"6-string", "id"=>"24", "parentId"=>"Guitars"}, 
{"__content__"=>"7-string", "id"=>"25", "parentId"=>"Guitars"}, 
{"__content__"=>"8-string", "id"=>"26", "parentId"=>"Guitars"}] 

Wie kann ich es tun?

Answer 1

Ich ziehe diese array-hash für eine bessere maping nasted zu ändern.

Eingang

arr = [ 
    {"__content__" => "Guitars", "id" => "2"}, 
    {"__content__" => "For Guitars", "id" => "3", "parentId" => "2"}, 
    {"__content__" => "6-string", "id" => "24", "parentId" => "2"}, 
    {"__content__" => "7-string", "id" => "25", "parentId" => "2"}, 
    {"__content__" => "8-string", "id" => "26", "parentId" => "2"} 
] 

erstellen Eltern

parents = arr.each_with_object({}) { |h, exp| exp[h['id']] = h['__content__'] } 

Nach dieser guten Map-Struktur können Sie einfach map Methode verwenden.

Prozess

output = arr.map do |h| 
    h['parentId'] = parents[h['parentId']] if h['parentId'] && parents[h['parentId']] 
    h 
end 

Ausgang

p output 

# [ 
# {"__content__" => "Guitars", "id" => "2"}, 
# {"__content__" => "For Guitars", "id" => "3", "parentId" => "Guitars"}, 
# {"__content__" => "6-string", "id" => "24", "parentId" => "Guitars"}, 
# {"__content__" => "7-string", "id" => "25", "parentId" => "Guitars"}, 
# {"__content__" => "8-string", "id" => "26", "parentId" => "Guitars"} 
# ] 

Ich hoffe, das hilft.

EDIT

Sie auch auf diese Weise

Art von ID verwenden können

arr.sort_by! { |h| h['id'] } 

Prozess

output = arr.each_with_object({}) do |h, exp| 
    exp[h['id']] = h 
    h['parentId'] = exp[h['parentId']]['__content__'] if h['parentId'] && exp[h['parentId']] 
    h 
    end 

danach werden Sie Hash mit id haben wie Schlüssel, so dass für die Ausgabe:

Ausgang

p output.values 

# [ 
# {"__content__"=>"Guitars", "id"=>"2"}, 
# {"__content__"=>"6-string", "id"=>"24", "parentId"=>"Guitars"}, 
# {"__content__"=>"7-string", "id"=>"25", "parentId"=>"Guitars"}, 
# {"__content__"=>"8-string", "id"=>"26", "parentId"=>"Guitars"}, 
# {"__content__"=>"For Guitars", "id"=>"3", "parentId"=>"Guitars"} 
# ] 

Answer 2

arr = [{"__content__"=>"Guitars", "id"=>"2"}, {"__content__"=>"For Guitars", "id"=>"3", "parentId"=>"2"}] 

id_content_mapping = arr.reduce({}) do |h, elt| 
    h[elt["id"]] = elt["__content__"] 
    h 
end 

arr.map do |elt| 
    if elt.has_key? "parentId" 
    elt["parentId"] = id_content_mapping[elt["parentId"]] 
    end 
    elt 
end 

Answer 3

Vorsicht! Die folgende Lösung mutiert den ursprünglichen Hash!

▶ hashes = [{"__content__"=>"Guitars", "id"=>"2"}, 
▷ {"__content__"=>"For Guitars", "id"=>"3", "parentId"=>"2"}, 
▷ {"__content__"=>"6-string", "id"=>"24", "parentId"=>"2"}, 
▷ {"__content__"=>"7-string", "id"=>"25", "parentId"=>"2"}, 
▷ {"__content__"=>"8-string", "id"=>"26", "parentId"=>"2"}] 

hashes.each_with_object({}) do |h, memo| 
    memo[h['id']] = h['__content__'] 
    h['parentId'] = memo[h['parentId']] 
end 

hashes 
#⇒ [{"__content__"=>"Guitars", "id"=>"2", "parentId"=>nil}, 
# {"__content__"=>"For Guitars", "id"=>"3", "parentId"=>"Guitars"}, 
# {"__content__"=>"6-string", "id"=>"24", "parentId"=>"Guitars"}, 
# {"__content__"=>"7-string", "id"=>"25", "parentId"=>"Guitars"}, 
# {"__content__"=>"8-string", "id"=>"26", "parentId"=>"Guitars"}]