clear
%% Find % Logical Operation, p.8
% 
A=[ 0, 0,-2; 
    0 -1 -1; 
   -2 -2  0];                  % add semicolon - look at warning!
index=find(A);                 % single numeration
[i,j,a]=find(A);
for k=1:nnz(A)
     disp([i(k),j(k),a(k)]);    % or [i(k),j(k),a(k)]    
end
%----------------------------
[i,j]=find(A==-2)               % with\without semicolon
[i(:),j(:)]
%---------------------------- 
A==-2;
A(A==-2)=pi
%----------------------------
%% Functions all & any, p.9-10
clear
% all
A=randi(9,5);
L=A==A';                         % issymmetric(A), isequal(A,A')?
all(L);                          % all(L(:))
S=A*A';
all(all(S==S'));  
% any
minA=min(A(:));                  % or minA=min(min(A))
B=A-minA;                        % contain zero
x=sort(B(:))
y=1./x;
logInd=isinf(y)
% help isrow (iscolumn,islogical,isempty,isfinite,isnan, isstruct,...)
x(logInd)=[]; y(logInd)=[]       % ?  
% or  x=x(isfinite(y)),          % ?
% y=y(isfinite(y)) %
plot(x,y)                        %
%% p.14 How do choose code, using presentation? Much better browser Edge!
% show step by step!

%% code is ready
clear
x=-pi:pi/24:pi;
y= sin(x)./x; % векторная операция
z=log((1+x.*sign(x)));
subplot(1,3,1);
plot(x,y);  hold on;
plot(x,z,'r-'); 
legend('sin(x)/x',...
             'log((1+x.*sign(x)))');
subplot(1,3,2);
% clear x % (если хотите)
x=linspace(1.6,3.1415,100); %
z=[sin(x)', tan(x)', sqrt(x)' x.^2'];
r=plot(z);
legend({'sin','tan','sqrt','x.^2'})
subplot(1,3,3)
plot(x,z);
legend({'sin(x)','tan(x)',...
          'sqrt(x)','x.^2'});
set(r(:),'linewidth',2);
set(gca,'fontsize',14);

set(r(1))                % all structure's fields
set(r(1),'Marker')
set(r(1),'LineStyle')
%% plpotyy yyaxis p.15
figure
% for different growth:
plotyy(x,sin(x),x,z(:,2))  % the first way
figure
yyaxis left % the second way
plot(x,sin(x))
gcl=gca
set(gca)
yyaxis right
plot(x,z(:,2))
gcr=gca
chr=get(gcr, "Children")
% design 
set(chr, "LineWidth",2)
%% code p.15 -> comment
clear
x=-pi:pi/24:1.4*pi; y= sin(x); z=exp(x);
    subplot(1,2,1);
title('sin(x) {\it падает} на ось X')
plot(x,y,'m--','linewidth',2);  hold on
plot(x,z,'c:','linewidth',2); 
lg1=legend('y=sin(x)','z=exp(x)');
lg1.FontSize=14;
xlabel('x'), 
yl=ylabel('y,z','rotation',0), 
yl.FontSize=14
set(gca,'fontsize',14)
    subplot(1,2,2);   
title('Каждому – свой Y!')
[haxes,line1,line2]=plotyy(x,y,x,z);
line1.LineWidth=2; 
line2.LineWidth=2;
xlabel('x');  grid on;
ylabel(haxes(1),'y','rotation',0);
ylabel(haxes(2),'z','rotation',0);
legend('y=sin(x)','z=exp(x');
set(haxes(1),'fontsize',14);
set(haxes(2),'fontsize',14)