MATLAB: Error using the randi function

errorrandi

Here is my code:
function EPS
Score=zeros(1,20);
X=[0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1];
for j=1:20
Dealer=X(randi(numel(X)));
if sum(X)-.5*length(X)==0
Pick=X(randi(numel(X)));
else
    if sum(X)>size(X)
        Pick=1;
    if sum(X)<size(X)
        Pick=0;
    end
    end
end
if Pick==Dealer
    Score(j)=1;
end
X=X(X~=Dealer);
end
disp(sum(Score)/20);
end
When I run this I get an error on line 11 (Dealer variable as the for loop is line 10): Error using randi First input must be a positive scalar integer value IMAX, or two integer values [IMIN IMAX] with IMIN less than or equal to IMAX.
If I define X as I did in my code and in my command window type X(randi(numel(X))) I do not get an error.
Why is my code giving me the error if in the command window it is working?

Best Answer

Score=zeros(1,20);
X=[0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,1,1,1,1];
for j=1:20
    idx = randi(numel(X)) ;
    Dealer=X(idx);
    if sum(X)-.5*length(X)==0
        Pick=X(randi(numel(X)));
    else
        if sum(X)>size(X)
            Pick=1;
            if sum(X)<size(X)
                Pick=0;
            end
        end
    end
    if Pick==Dealer
        Score(j)=1;
    end
    X(idx) = [] ;
end
disp(sum(Score)/20);
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