Using while loop to analyze cell array

Let's say I have a cell array that is 1x10000. The variable name given to the dataset is data.

So i want to be able to use a cell in the array, the cell before, and the cell after the center cell. so something along these lines:

cell before = n-1

cell after = n+1

So in the while loop I want to do some thing like this:

 while n < length(data)
      n = data;
      before = n-1;
      after = n+1;

      eq = (abs(n - ((before+after)/2))/((before+after)/2))*100;
 end

I dont believe this is entirely correct, any input on what needs to be changed?

Answer 1

[per isakson]

Why a cell array of numeric data rather than a numeric array? Many questions are about removing loops. Why a while-loop?

This is more like the Matlab way:

    N = 1000;
    data = rand( N, 1 );
    tmp = (data(1:end-2)+data(3:end))/2;
    out = 100*abs( data(2:end-1) - tmp )./ tmp;
    plot( out )

.

--- Another example ---

    N = 100;
    n = transpose( (1:N) );
    data    = sin( 2*pi*n/N ); 
    before  = [ nan; data( 1 : end-1 ) ];
    after   = [ data( 2 : end ); nan ];
    plot( n, [ before, data, after ], '.' )
    tmp = ( before + after ) / 2;
    out = 100*abs( data - tmp )./ tmp;   % eq is the name of a function
    plot( n, data-tmp, '.' )
    plot( n, out, '.' )

.

See "Evaluate Subsections of Files Using Code Cells" in the documentation and evaluate the cells one at a time.