MATLAB: Find index of an arry in matlab

findismember

I have a big array and i want to find the index of the element of an array in the big array.

I know this could be easily solves with functions such find or ismember. But my goal is to give the index of the first number in the case when the the number is present more than one time in the big array like the numbers 2.2, 5.1, 6 and 7.

e.g

BigArray=[1 2 2.2 3 2.2 5 5.1 5.1 6 6 7 7………]

ArryToBeFound=[1 2 2.2 5.1 6 7]

Solution:

index=[1 2 3 7 9 11]

Do you have any idea how to solve this?

Thank you

Best Answer

ismember is indeed the functio to use:

[~, where] = ismember(ArrayToBeFound, BigArray)

where is the index of the 1st element where the element is found, or 0, if not found. ismember guarantees that it's always the first index.

Related Solutions

MATLAB: Creating Arrys from another big array

 index=[1 25 40 63 77 99 100]
 A = rand(1,100);
 for i = 1:numel(index)-1
   B{i} = A(index(i):index(i+1));
 end

Note that the index(2), index(3), ... index(N-1) elements occur twice in B, such that B has numel(index) -2 elements more than A.

MATLAB: 2d arry sorting

Hi,

is this what you want?

Cheers!

Renato

 clear
 a(1,:)=[1,2,3,4,10,11,12,13,19,20,21,22];
 a(2,:)=[4,1,3,2,4,3,1,2,3,2,4,1];
 a(3,:)=[1,2,3,4,5,6,7,8,9,10,11,12];
 N = size(a,2);
 %Create 4th row
 a(4,1) = 0;
 a(4,2:end) = a(1,2:end) - a(1,1:end-1);
 delta = 3;
 i1 = 1;
 for i = 1:N
    %find range to sort i1:i2
    if i == N || a(4,i+1) > delta
        i2 = i;
        %extract the part of the 2d-array to be sorted
        tmp_a = a(1:2,i1:i2);
        [~, I] = sort(tmp_a(2,:));
        %put it back in the 2d-array
        a(1:2,i1:i2) = tmp_a(1:2, I);
        i1 = i+1;
    end
 end

Best Answer

Related Solutions

MATLAB: Creating Arrys from another big array

MATLAB: 2d arry sorting

Related Question