MATLAB: Replace elements in an Array with other elements

find

hi all,

i have the folwing situation:

i have an array:

A=[1 2 3 4 4 4 5 8 7 4 6 4]

i want to find the element equal to the value 4.

I do this:

index=find(A==4)

i want now to replace the element with this index with the previous value. it means i want to get:

A_new=[1 2 3 3 3 3 5 8 7 7 6 6].

i did it with a loop. is there any method without loop?

thank you

Best Answer

While it may be possible to do it without a loop, with a combination of diff, find and possibly cumsum it's going to be a lot more obscure than a simple loop and probably not any more efficient.

The simplest loop would be:

for idx = find(A == 4)
   A(idx) = A(idx-1);
end

which also works for consecutive elements to replace.

Related Solutions

MATLAB: Insert elements into vector

index = [1;2;4;5;6;8;9];
index_val = [11;25;3;4;56;7;9];
removed_index = [7,3];   % simpler to use a numeric array

removed_val = [1.1,3.2]; % simpler to use a numeric array

Then all you need is:

idx = [index(:);removed_index(:)];
vec = [index_val(:);removed_val(:)];
vec(idx) = vec
idx(idx) = idx

MATLAB: Regression with some part of the array

x = [ 1 5 6 7 8 3 2 ];
y = [ 2 9 4 6 4 5 6 ];
idx = find(x > 3); % Returns the indexes where x is larger than 3
plotregression(x(idx), y(idx)); % Only uses the indexes of the vectors, where x were larger than 3

Replace with other regression methods, depending on what you need.

Best Answer

Related Solutions

MATLAB: Insert elements into vector

MATLAB: Regression with some part of the array

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