Sorting a list based on the order of another list
Question:
I have the following list:
I=[1,4, 3, 7,8,9]
I have another two lists which are subsets of list I:
IU=[3,9]
IUU=[4,8]
I have to merge lists IU and IUUto create list J in such a way that the elements of the merged list follow the orders of the elements of list I.
J=[4,3,8,9]
I am looking for some ideas on how to implement this. If I just add the sublist I get following result.
J=IU+IUU
J=[3, 9, 4, 8]
I will appreciate your comments/answers.
Answers:
I found the answer. Thanks for looking.
sorted(J,key=I.index)
You can just do something like:
sorted(IU + IUU, key={e:i for i,e in enumerate(I)}.get)
Which should be O(N*Log N)
The problem with key=I.index is that this will force your performance to deteriorate to O(N**2).
I have the following list:
I=[1,4, 3, 7,8,9]
I have another two lists which are subsets of list I:
IU=[3,9]
IUU=[4,8]
I have to merge lists IU and IUUto create list J in such a way that the elements of the merged list follow the orders of the elements of list I.
J=[4,3,8,9]
I am looking for some ideas on how to implement this. If I just add the sublist I get following result.
J=IU+IUU
J=[3, 9, 4, 8]
I will appreciate your comments/answers.
I found the answer. Thanks for looking.
sorted(J,key=I.index)
You can just do something like:
sorted(IU + IUU, key={e:i for i,e in enumerate(I)}.get)
Which should be O(N*Log N)
The problem with key=I.index is that this will force your performance to deteriorate to O(N**2).