CODEWITHSUNDEEP
matlabmatrixmapping
ocean800
ocean800

Reputation: 3737

Keeping track of mapped values of a matrix?

So I had a large matrix(4091252x2) with large values like this: 

 439105     1053224
  439105     1696241
  439105      580064
  439105     1464748
 1836139     1593258
 1464748      439105
 1464748     1053224
 1464748     1696241
 1464748      580064
  580064      439105

that I mapped down to smaller numbers. However, how would I keep track of the numbers that I mapped?

For example, assuming that I have a matrix like 

A = [110  503 
     402  110
     300  900
     300  402]

and mapped it to: 

B = [1  4 
     3  1
     2  5 
     2  3]

using: 

[~,~,D] = unique(A);
B = reshape(D,size(A))

How could I write a function to keep track of the values that I mapped? For example that 110 = 1? I'm just not sure how to approach the problem, and any help would be greatly appreciated, thank you!!

Upvotes: 3

Views: 66

Answers (1)

user1543042
user1543042

Reputation: 3440

It maps in order so first output

[largeMap,~,D] = unique(A);
B = reshape(D,size(A)) ;
smallMap = (1:length(largeMap))';
map = [largeMap, smallMap];

Upvotes: 2

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