# Connecting the point selectively

1. Apr 24, 2015

### hokhani

Running the Matlab code below two discrete regions appear; one in left and the other in right.
Code (Text):

x=20:5:800;
xpr=x*pi/180;
y=sin(xpr);
n=find(y<.2);
plot(x(n),y(n),'*')

I would like to connect the points of each region together and not to connect the rightmost point of the left region to the leftmost point of the right region so that the two regions remain separated. What should I do? I appreciate any help.

2. Apr 24, 2015

### kreil

Code (Text):

x=20:5:800;
xpr=x*pi/180;
y=sin(xpr);
n=find(y<.2);

X = xpr(n);
Y = y(n);
N = length(X)/2;
plot(X(1:N), Y(1:N), '-*', X(N+1:end), Y(N+1:end), '-*')

Since you scaled x to xpr, I plotted xpr since it is used to calculate y. But essentially all I did was break X and Y in half, then plot the first and second halves separately in the call to plot. The '-*' ensures that plot draws the point and connects with a line. The result is below. Note that since the plots are separate, they get different colors. You can get around that by specifying the same color for both, for example by saying '-*b' to make both plots blue.