matlab中 hold on 与hold off的用法

hold on 是当前轴及图形保持而不被刷新，准备接受此后将绘制

hold off 使当前轴及图形不在具备被刷新的性质

>> t=(0:pi/100:pi)';       
y1=sin(t)*[1,-1];      
y2=sin(t).*sin(9*t);       
t3=pi*(0:9)/9;               
y3=sin(t3).*sin(9*t3);             
plot(t,y1,'r:',t,y2,'-bo')            
hold on     
plot(t3,y3,'s','MarkerSize',10,'MarkerEdgeColor',[0,1,0],'MarkerFaceColor',[1,0.8,0]) 
axis([0,pi,-1,1])           
hold off

图形

>> t=(0:pi/100:pi)';       
y1=sin(t)*[1,-1];      
y2=sin(t).*sin(9*t);       
t3=pi*(0:9)/9;               
y3=sin(t3).*sin(9*t3);             
plot(t,y1,'r:',t,y2,'-bo')            
plot(t3,y3,'s','MarkerSize',10,'MarkerEdgeColor',[0,1,0],'MarkerFaceColor',[1,0.8,0]) 
axis([0,pi,-1,1])           
hold off

去掉hold on后的图形，只显示最后的一次数据