MATLAB: How to exclude certain values from an array

arrayplot

I am trying to plot a log equation, before I can I need to calculate x.
x can sometimes be returned as 0 or 1 so I need to exclude these points before I plot the log graph.
How do I achieve this?
So far I have tried this fairly inefficient way, and it doesnt seem to be excluding them from the array just not plotting them on the graph so that when i get to the last function to calculate p it doesnt calculate it for the whole array just one value:
xi1 = hits1./tot1
yi1=log(xi1./(1-xi1));
xplot1 = xi1
yplot1 = yi1;
xplot1(xplot1==0) = NaN;
yplot1(yplot1==0) = NaN;
xplot1(xplot1==1) = NaN;
yplot1(yplot1==1) = NaN;
xplot1(xplot1==-Inf) = NaN;
yplot1(yplot1==-Inf) = NaN;
xplot1(xplot1==Inf) = NaN;
yplot1(yplot1==Inf) = NaN;
figure(1)
plot(xplot1, yplot1,'linestyle','none','marker','o')
hold on
p1 = 4.8422;
p2 = -2.4067;
y = (p1.*xi1) + p2
plot(xi1, y)
hold off
p = 1/(1+exp(-((p1.*xi1) + p2)))
figure(3)
plot(xi1, p)

Best Answer

If you want to remove them then use [] instead of NaN
xi1 = hits1./tot1
yi1=log(xi1./(1-xi1));
xplot1 = xi1
yplot1 = yi1;
mask = (xplot1==0) | (xplot1==1) | (isinf(xplot1));
xplot1(mask) = [];
yplot1(mask) = [];
figure(1)
plot(xplot1, yplot1,'linestyle','none','marker','o')
hold on
p1 = 4.8422;
p2 = -2.4067;
y = (p1.*xi1) + p2
plot(xi1, y)
hold off
p = 1/(1+exp(-((p1.*xi1) + p2)))
figure(3)
plot(xi1, p)
I haven't written a separate mask for yplot1 because I assume both have invalid elements at matching locations. If not, then you can similarly write a mask for yplot1
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