Question

i have an array

[['Part', 'create'], ['Part', 'update'], ['Part', 'delete'], ['Part', 'release'], ['Plan', 'create'], ['Plan', 'update'], ['Plan', 'delete'], ['Plan', 'release'], ['Inspection', 'create'], ['Inspection', 'update'], ['Inspection', 'delete'], ['Inspection', 'release'], ['User', 'create'],['User', 'update']]

i want it to be sorted in order of Part, Plan, Inspection and create, update, delete, release

the way i want it to be sorted in the above order is cause

Part 
  has_many plans
Plan 
  belongs_to :part
  has_many inspections
Inspection
  belongs_to :plan

i have implemented dynamic roles and permissions using cancan. the user needs to be assigned permissions for the actions(create, update, delete, release) and the order of display of the
SubjectClass(Part, Plan, Inspection, User) must be as their relationship.

when i used sort, i get

a.sort
 => [["Inspection", "create"], ["Inspection", "delete"], ["Inspection", "release"], ["Inspection", "update"], ["Part", "create"], ["Part", "delete"], ["Part", "release"], ["Part", "update"], ["Plan", "create"], ["Plan", "delete"], ["Plan", "release"], ["Plan", "update"], ["User", "create"], ["User", "update"]] 

a.sort_by{|x, y| x[0] <=> y[0]}
=> [["Part", "create"], ["Part", "update"], ["Part", "delete"], ["Part", "release"], ["Plan", "create"], ["Plan", "update"], ["Plan", "delete"], ["Plan", "release"], ["Inspection", "create"], ["Inspection", "update"], ["Inspection", "delete"], ["Inspection", "release"], ["User", "create"], ["User", "update"]] 

can index method be used in someway? Also new subjectclasses and actions maybe added later. So sorting order may change.

Answer 1

a = [['Part', 'create'], ['Part', 'update'], ['Part', 'delete'], ['Part', 'release'], ['Plan', 'create'], ['Plan', 'update'], ['Plan', 'delete'], ['Plan', 'release'], ['Inspection', 'create'], ['Inspection', 'update'], ['Inspection', 'delete'], ['Inspection', 'release'], ['User', 'create'],['User', 'update']]
order = [%w{Part Plan Inspection}, %w{create update delete release}]

If we assume that all unspecified elements have weight of 999 (such as User in your example), this will sort the input array in a given order:

a.sort_by{|e| e.zip(order).map{|i,j| j.index(i) || 999}}
=> [["Part", "create"],
 ["Part", "update"],
 ["Part", "delete"],
 ["Part", "release"],
 ["Plan", "create"],
 ["Plan", "update"],
 ["Plan", "delete"],
 ["Plan", "release"],
 ["Inspection", "create"],
 ["Inspection", "update"],
 ["Inspection", "delete"],
 ["Inspection", "release"],
 ["User", "create"],
 ["User", "update"]]