How to shift elements of an array to the left without using loops in matlab?

I have a fixed sized array in Matlab. When I want to insert a new element I do the following:

1. To make room first array element will be overwritten
2. Every other element will be shifted at new location index-1 ---left shift.
3. The new element will be inserted at the place of last element which becomes empty by shifting the elements.

I would like to do it without using any loops.

3 Answers

I'm not sure I understand your question, but I think you mean this:

A = [ A(1:pos) newElem A((pos+1):end) ] 

That will insert the variable (or array) newElem after position pos in array A.

Let me know if that works for you!

[Edit] Ok, looks like you actually just want to use the array as a shift register. You can do it like this:

A = [ A(2:end) newElem ] 

This will take all elements from the 2nd to the last of A and added your newElem variable (or array) to the end.

The circshift function is another solution:

B = circshift(A,shiftsize) circularly shifts the values in the array, A, by shiftsize elements. shiftsize is a vector of integer scalars where the n-th element specifies the shift amount for the n-th dimension of array A. If an element in shiftsize is positive, the values of A are shifted down (or to the right). If it is negative, the values of A are shifted up (or to the left). If it is 0, the values in that dimension are not shifted.

Example:

Circularly shift first dimension values down by 1 and second dimension values to the left by 1.

A = [ 1 2 3;4 5 6; 7 8 9] A = 1 2 3 4 5 6 7 8 9 B = circshift(A,[1 -1]); B = 8 9 7 2 3 1 5 6 4 

simply, remove the first value in the array and append the new one at the end.

A(1) = [] A = [A newValue] 

Numeric example

A = [1 2 3 4]; A(1) = []; A = [A 5]; 

The result is A having values [2, 3, 4, 5]