Removing a particular legend from plot

clear all
clc

k1=0.7;
k2=01;
wf=1;

ws=1.5;
b=0.15;
d=0.15;
a=0.15;
h=0.05;
j=0;
l=0;
ns1=0;
ns2=0;
nu=0;

for Zf= 0.01:0.01:1.5
   
    n=0;
    zf=Zf;
    u7=-pi;
    u5=pi*(wf^2 + 2*zf*(a + h)*wf + ws^2 + a*h + 1);
    u3=(-pi*(wf^2*(ws^2 + a*h + 1) - k1*k2 + ws^2 + 2*wf*zf*(h*ws^2 + a)));
    u2=8*b*d*wf*ws^2*zf;
    u1=pi*(wf^2*ws^2 - k1*k2*ws^2);
    
    v6=pi*(a + h + 2*wf*zf);
    v4=(-pi*(a + wf^2*(a + h) + h*ws^2 + 2*wf*zf*(ws^2 + a*h + 1)));
    v3=4*b*d*ws^2;
    v2=pi*(wf^2*(h*ws^2 + a) + 2*wf*ws^2*zf - a*k1*k2);
    v1=(-4*b*d*wf^2*ws^2);
    j4=v3*u7;
    j3=v3*u5+v1*u7-u2*v6;
    j2=v3*u3+v1*u5-u2*v4;
    j1=v3*u1+v1*u3-u2*v2;
    j0=v1*u1;
    j=[j4 j3 j2 j1 j0];
    jr=roots(j);
    w=jr.^0.5;
    for i=1:size(w)
        if imag(w(i,1))==0
            o=w(i,1);
            A=-u2*o^2/(u7*o^7+u5*o^5+u3*o^3+u1*o);
            
            if A>0
                d1=6*A*pi*(a + h + 2*wf*zf)*o^5 + (-4*A*pi*(a + wf^2*(a + h) + h*ws^2 + 2*wf*zf*(ws^2 + a*h + 1)))*o^3 + 12*b*d*ws^2*o^2 + 2*A*pi*(wf^2*(h*ws^2 + a) + 2*wf*ws^2*zf - a*k1*k2)*o - 4*b*d*wf^2*ws^2;
                d2=- pi*o^7 + pi*(wf^2 + 2*zf*(a + h)*wf + ws^2 + a*h + 1)*o^5 - pi*(wf^2*(ws^2 + a*h + 1) - k1*k2 + ws^2 + 2*wf*zf*(h*ws^2 + a))*o^3 + pi*(wf^2*ws^2 - k1*k2*ws^2)*o;
                d3=(-7*pi*A)*o^6 + 5*A*pi*(wf^2 + 2*zf*(a + h)*wf + ws^2 + a*h + 1)*o^4 + (-3*A*pi*(wf^2*(ws^2 + a*h + 1) - k1*k2 + ws^2 + 2*wf*zf*(h*ws^2 + a)))*o^2 + 16*b*d*wf*ws^2*zf*o + pi*A*(wf^2*ws^2 - k1*k2*ws^2);
                d4=pi*(a + h + 2*wf*zf)*o^6 - pi*(a + wf^2*(a + h) + h*ws^2 + 2*wf*zf*(ws^2 + a*h + 1))*o^4 + pi*(wf^2*(h*ws^2 + a) + 2*wf*ws^2*zf - a*k1*k2)*o^2;
                D=d1*d2-d3*d4;
                l=l+1;
                R(l,1)=A;
                R(l,2)=o;
                R(l,3)=D/abs(D);
            end
            
        end
    end
   
    R=sortrows(R,-1);
  
    for k=1:size(R,1)
              
        if R(k,3)==1
            n=n+1;
           if n==1;
               ns1=ns1+1;
               As1(ns1)=R(k,1);
               Zfs1(ns1)=zf;
           elseif n==2
               ns2=ns2+1;
               As2(ns2)=R(k,1);
               Zfs2(ns2)=zf;
           end
        end
        
        if R(k,3)==-1
            nu=nu+1;
            Au(nu)=R(k,1);
            Zfu(nu)=zf;
        end
    end
   R=0;l=0;
end
if ns1>0
   plot(Zfs1,As1,'-k')
    hold on
end
if ns2>0
  plot(Zfs2,As2,'-k')
    hold on
end

if nu>0
    plot(Zfu,Au,':k')
end
legend

You can see the plot data 1 and data 2 are ploted with same property of line therefore i want to rmove the legend even the legend mark from data 2

Answer 1

[Star Strider]

The first two lines have the same line style.

To see them individually, choose a different line style for each.

To label them in the legend, use the DisplayName option as described in Specify Legend Labels During Plotting Commands.

I did that in this minor revision of the posted code —

k1=0.7;
k2=01;
wf=1;

ws=1.5;
b=0.15;
d=0.15;
a=0.15;
h=0.05;
j=0;
l=0;
ns1=0;
ns2=0;
nu=0;

for Zf= 0.01:0.01:1.5
    
    n=0;
    zf=Zf;
    u7=-pi;
    u5=pi*(wf^2 + 2*zf*(a + h)*wf + ws^2 + a*h + 1);
    u3=(-pi*(wf^2*(ws^2 + a*h + 1) - k1*k2 + ws^2 + 2*wf*zf*(h*ws^2 + a)));
    u2=8*b*d*wf*ws^2*zf;
    u1=pi*(wf^2*ws^2 - k1*k2*ws^2);
    
    v6=pi*(a + h + 2*wf*zf);
    v4=(-pi*(a + wf^2*(a + h) + h*ws^2 + 2*wf*zf*(ws^2 + a*h + 1)));
    v3=4*b*d*ws^2;
    v2=pi*(wf^2*(h*ws^2 + a) + 2*wf*ws^2*zf - a*k1*k2);
    v1=(-4*b*d*wf^2*ws^2);
    j4=v3*u7;
    j3=v3*u5+v1*u7-u2*v6;
    j2=v3*u3+v1*u5-u2*v4;
    j1=v3*u1+v1*u3-u2*v2;
    j0=v1*u1;
    j=[j4 j3 j2 j1 j0];
    jr=roots(j);
    w=jr.^0.5;
    for i=1:size(w)
        if imag(w(i,1))==0
            o=w(i,1);
            A=-u2*o^2/(u7*o^7+u5*o^5+u3*o^3+u1*o);
            
            if A>0
                d1=6*A*pi*(a + h + 2*wf*zf)*o^5 + (-4*A*pi*(a + wf^2*(a + h) + h*ws^2 + 2*wf*zf*(ws^2 + a*h + 1)))*o^3 + 12*b*d*ws^2*o^2 + 2*A*pi*(wf^2*(h*ws^2 + a) + 2*wf*ws^2*zf - a*k1*k2)*o - 4*b*d*wf^2*ws^2;
                d2=- pi*o^7 + pi*(wf^2 + 2*zf*(a + h)*wf + ws^2 + a*h + 1)*o^5 - pi*(wf^2*(ws^2 + a*h + 1) - k1*k2 + ws^2 + 2*wf*zf*(h*ws^2 + a))*o^3 + pi*(wf^2*ws^2 - k1*k2*ws^2)*o;
                d3=(-7*pi*A)*o^6 + 5*A*pi*(wf^2 + 2*zf*(a + h)*wf + ws^2 + a*h + 1)*o^4 + (-3*A*pi*(wf^2*(ws^2 + a*h + 1) - k1*k2 + ws^2 + 2*wf*zf*(h*ws^2 + a)))*o^2 + 16*b*d*wf*ws^2*zf*o + pi*A*(wf^2*ws^2 - k1*k2*ws^2);
                d4=pi*(a + h + 2*wf*zf)*o^6 - pi*(a + wf^2*(a + h) + h*ws^2 + 2*wf*zf*(ws^2 + a*h + 1))*o^4 + pi*(wf^2*(h*ws^2 + a) + 2*wf*ws^2*zf - a*k1*k2)*o^2;
                D=d1*d2-d3*d4;
                l=l+1;
                R(l,1)=A;
                R(l,2)=o;
                R(l,3)=D/abs(D);
            end
            
        end
    end
    
    R=sortrows(R,-1);
    
    for k=1:size(R,1)
        
        if R(k,3)==1
            n=n+1;
            if n==1;
                ns1=ns1+1;
                As1(ns1)=R(k,1);
                Zfs1(ns1)=zf;
            elseif n==2
                ns2=ns2+1;
                As2(ns2)=R(k,1);
                Zfs2(ns2)=zf;
            end
        end
        
        if R(k,3)==-1
            nu=nu+1;
            Au(nu)=R(k,1);
            Zfu(nu)=zf;
        end
    end
    R=0;l=0;
end
if ns1>0
    plot(Zfs1,As1,'-k', 'DisplayName','ns_1 > 0')
    hold on
end
if ns2>0
    plot(Zfs2,As2,'-k', 'DisplayName','ns_2 > 0')
    hold on
end

if nu>0
    plot(Zfu,Au,':k', 'DisplayName','nu > 0')
end
legend

.

[Joy Mondal]

Thanks Star strider for your support. But i got another command to hide the legend from appearing in the figure that can eliminate the legend

plot(x,y,'HandleVisibility','off')

[Star Strider]

My pleasure.

Or just comment-out the legend call.

Is there a particular reason to create the legend in the first place and then hide it so It won’t display? That just seems inefficient to me.

.

[Joy Mondal]

Actually the solid lines are stable solutions for a particular value of a parametr & dashed one is the unstable one..that is why i am trying to hide it from legend only one solid line is sufficient to describe the plot... thanks.

[Star Strider]

That was not obvious before.

That solution is straightforward. Change the if block and plot calls respectively to —

if ns1>0

hp{1} = plot(Zfs1,As1,'-k', 'DisplayName','ns_1 > 0');

hold on

end

if ns2>0

hp{2} = plot(Zfs2,As2,'-k', 'DisplayName','ns_2 > 0');

hold on

end

if nu>0

hp{3} = plot(Zfu,Au,':k', 'DisplayName','nu > 0');

end

legend([hp{[1 2]}], 'Location','best')

Note that ‘hp{3}’ exists if using it later is desired, although it is not used here. See Included Subset of Graphics Objects in Legend to documentation on that legend option.

I already made those changes in this version of the code, and those results are displayed in the plot —

k1=0.7;
k2=01;
wf=1;

ws=1.5;
b=0.15;
d=0.15;
a=0.15;
h=0.05;
j=0;
l=0;
ns1=0;
ns2=0;
nu=0;

for Zf= 0.01:0.01:1.5
    
    n=0;
    zf=Zf;
    u7=-pi;
    u5=pi*(wf^2 + 2*zf*(a + h)*wf + ws^2 + a*h + 1);
    u3=(-pi*(wf^2*(ws^2 + a*h + 1) - k1*k2 + ws^2 + 2*wf*zf*(h*ws^2 + a)));
    u2=8*b*d*wf*ws^2*zf;
    u1=pi*(wf^2*ws^2 - k1*k2*ws^2);
    
    v6=pi*(a + h + 2*wf*zf);
    v4=(-pi*(a + wf^2*(a + h) + h*ws^2 + 2*wf*zf*(ws^2 + a*h + 1)));
    v3=4*b*d*ws^2;
    v2=pi*(wf^2*(h*ws^2 + a) + 2*wf*ws^2*zf - a*k1*k2);
    v1=(-4*b*d*wf^2*ws^2);
    j4=v3*u7;
    j3=v3*u5+v1*u7-u2*v6;
    j2=v3*u3+v1*u5-u2*v4;
    j1=v3*u1+v1*u3-u2*v2;
    j0=v1*u1;
    j=[j4 j3 j2 j1 j0];
    jr=roots(j);
    w=jr.^0.5;
    for i=1:size(w)
        if imag(w(i,1))==0
            o=w(i,1);
            A=-u2*o^2/(u7*o^7+u5*o^5+u3*o^3+u1*o);
            
            if A>0
                d1=6*A*pi*(a + h + 2*wf*zf)*o^5 + (-4*A*pi*(a + wf^2*(a + h) + h*ws^2 + 2*wf*zf*(ws^2 + a*h + 1)))*o^3 + 12*b*d*ws^2*o^2 + 2*A*pi*(wf^2*(h*ws^2 + a) + 2*wf*ws^2*zf - a*k1*k2)*o - 4*b*d*wf^2*ws^2;
                d2=- pi*o^7 + pi*(wf^2 + 2*zf*(a + h)*wf + ws^2 + a*h + 1)*o^5 - pi*(wf^2*(ws^2 + a*h + 1) - k1*k2 + ws^2 + 2*wf*zf*(h*ws^2 + a))*o^3 + pi*(wf^2*ws^2 - k1*k2*ws^2)*o;
                d3=(-7*pi*A)*o^6 + 5*A*pi*(wf^2 + 2*zf*(a + h)*wf + ws^2 + a*h + 1)*o^4 + (-3*A*pi*(wf^2*(ws^2 + a*h + 1) - k1*k2 + ws^2 + 2*wf*zf*(h*ws^2 + a)))*o^2 + 16*b*d*wf*ws^2*zf*o + pi*A*(wf^2*ws^2 - k1*k2*ws^2);
                d4=pi*(a + h + 2*wf*zf)*o^6 - pi*(a + wf^2*(a + h) + h*ws^2 + 2*wf*zf*(ws^2 + a*h + 1))*o^4 + pi*(wf^2*(h*ws^2 + a) + 2*wf*ws^2*zf - a*k1*k2)*o^2;
                D=d1*d2-d3*d4;
                l=l+1;
                R(l,1)=A;
                R(l,2)=o;
                R(l,3)=D/abs(D);
            end
            
        end
    end
    
    R=sortrows(R,-1);
    
    for k=1:size(R,1)
        
        if R(k,3)==1
            n=n+1;
            if n==1;
                ns1=ns1+1;
                As1(ns1)=R(k,1);
                Zfs1(ns1)=zf;
            elseif n==2
                ns2=ns2+1;
                As2(ns2)=R(k,1);
                Zfs2(ns2)=zf;
            end
        end
        
        if R(k,3)==-1
            nu=nu+1;
            Au(nu)=R(k,1);
            Zfu(nu)=zf;
        end
    end
    R=0;l=0;
end
if ns1>0
    hp{1} = plot(Zfs1,As1,'-k', 'DisplayName','ns_1 > 0');
    hold on
end
if ns2>0
    hp{2} = plot(Zfs2,As2,'-k', 'DisplayName','ns_2 > 0');
    hold on
end

if nu>0
    hp{3} = plot(Zfu,Au,':k', 'DisplayName','nu > 0');
end
legend([hp{[1 2]}], 'Location','best')

I still believe that using different line styles would make the plot easier to interpret.

Experiment to get different results.

.