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Re: Compare two vectors and got indices of the identical numbers
Posted:
Feb 16, 2013 8:48 PM


On 2/16/2013 6:52 PM, Nasser M. Abbasi wrote: > On 2/16/2013 5:53 PM, Danny wrote: >> How to compare 2 vectors and got the indices of 2 identical numbers >> >> lets say I have matrix a >>>> a=[250;500;750;200;600;800;230;650;800] >> >> a = >> >> 250 >> 500 >> 750 >> 200 >> 600 >> 800 >> 230 >> 650 >> 800 >> >> and I sort matrix a to matrix b >> >>>> b=sort(a) >> >> b = >> >> 200 >> 230 >> 250 >> 500 >> 600 >> 650 >> 750 >> 800 >> 800 >> >> and I want to compare matrix b to matrix a to identify in which indices of matrix a is >> equal to the content of matrix b. >> >> For example for the number 230 in matrix b is located in the indices of #7 in matrix a >> or number 650 in matrix b is located in the indices of #8 in matrix a >> >> Thanks before for the answer >> >> Regards >> > > one way: > >  > a=[250;500;750;200;600;800;230;650;800]; > b=sort(a,1); > N=length(a); > for i=1:N > [~,N(i)]=ismember(b(i),a); > end > N >  > > 4 7 1 2 5 8 3 9 9 >
I just noticed this can be done in one command
K>> [~,J]=ismember(b,a)
J =
4 7 1 2 5 8 3 9 9



