Given I have two arrays, say:
a = [0.8, 0.2,0.1,20,1.5,5.8,12]
b = [2,1,3,1,2,2,3]
Now I want to order the entries in a according to the numbers in b, in that I would want to have all 1's first in the respective order, then the 2s, then the 3.., for these example arrays I would want to get the following:
c = [0.2,20,0.8,1.5,5.8,0.1,12]
How can I do that efficiently in MATLAB? Tks
First, sort b and get the indices of b in the sorted matrix (the second output of sort). Since this is a stable sort, order will be preserved. Then use those indices in a to get the resulting array:
>> a = [0.8, 0.2,0.1,20,1.5,5.8,12];
>> b = [2,1,3,1,2,2,3];
>> [~,I]=sort(b)
I =
2 4 1 5 6 3 7
>> a(I)
ans =
0.20000 20.00000 0.80000 1.50000 5.80000 0.10000 12.00000
