How can I get Greek letters to show up in my legend, if my legend is automated through a loop?

Question

Robert 2013-5-30

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/77543-how-can-i-get-greek-letters-to-show-up-in-my-legend-if-my-legend-is-automated-through-a-loop

My code is here (with random matrices to produce variables, for simplification). My issue is with the legend function.I am currently getting my legend from a cell. This is important because I am using this script for data processing several files at once, and with the number of those files changing from run to run. However, I want the Greek character 'Phi' to show up in the legend, though MATLAB is not interpreting it as 'tex' and I am just getting the characters '/Phi' in the plot legend. I assume it is something to do with the elements in legend_cell being of type 'char' but I haven't figured out what to do about that. Any help is much appreciated.

My code is as follows (this should be able to reproduce the problem if copied and pasted):

clc;
clear all;
%Values
x1=rand(250,12);
x1(:,1)=(0.5);
y1=rand(300,12);
y1(:,1)=(0.5);
z1=rand(150,12);
z1(:,1)=(0.5);
x2=rand(255,12);
x2(:,1)=(0.75);
y2=rand(350,12);
y2(:,1)=(0.75);
z2=rand(450,12);
z2(:,1)=(0.75);
x3=rand(155,12);
x3(:,1)=(1.25);
y3=rand(250,12);
y3(:,1)=(1.25);
z3=rand(300,12);
z3(:,1)=(1.25);
numfiles = 9;
vals = cell(1,numfiles);
vals_length = zeros(1,numfiles);
vals{1}=x1;
vals{2}=y1;
vals{3}=z1;
vals{4}=x2;
vals{5}=y2;
vals{6}=z2;
vals{7}=x3;
vals{8}=y3;
vals{9}=z3;
%get max dimensions
max_dim=0;
for i = 1:numfiles
    vals_length(i)=length(vals{i}(:,1));
    if vals_length(i)>max_dim
        max_dim=length(vals{i}(:,1));
    end
end
zero_rows_reqd=zeros(1,numfiles);
for i = 1:numfiles
    if vals_length(i)<max_dim
        zero_rows_reqd(i) = max_dim-vals_length(i);
        vals{i}=[vals{i}; zeros(zero_rows_reqd(i),12)];
    end
end
%Initialize Variables
spark = zeros(1,numfiles);
phi_nominal = zeros(1,numfiles);
for i = 1:numfiles;
    %Get variables
    a(:,i) = vals{i}(1:max_dim,1);
    b(:,i) = vals{i}(1:max_dim,2); %RPM
    c(:,i) = vals{i}(1:max_dim,3); %deg_Celsius
    d(:,i) = vals{i}(1:max_dim,4); %deg_Celsius
    e(:,i) = vals{i}(1:max_dim,5); %deg_Celsius
    f(:,i) = vals{i}(1:max_dim,6);
    g(:,i) = vals{i}(1:max_dim,7); % Amps
    h(:,i) = vals{i}(1:max_dim,8);% percent
    r(:,i) = vals{i}(1:max_dim,9); %deg_Celsius
    s(:,i) = vals{i}(1:max_dim,10); %kPa abs
    t(:,i) = vals{i}(1:max_dim,11); %kPa abs
    u(:,i) = vals{i}(1:max_dim,12);
end
plot_separator=a;   %Set plot separator here
plot_separator=unique(plot_separator);
%-----------------------------------------------Begin Plots---------------------------------
%Plot Markers:
markers='so*x+d^v.><ph';
%-----Plot ---------------
%Set Variable of Interest:
y_plot=h;
x_plot=a;
%------------
y_plot_mean=zeros(length(plot_separator),numfiles);
y_plot_std=zeros(length(plot_separator),numfiles);
%the following loop separates plots by seperator
for k=1:length(plot_separator);
    for i=1:numfiles
        if mean(a(1,i))==plot_separator(k)
            y_plot_mean(k,i)=mean(y_plot(1:vals_length(1,i),i));
            y_plot_std(k,i)=std(y_plot(1:vals_length(1,i),i));
        end
    end
end
%To not plot zeros:
y_plot_mean(y_plot_mean==0)=nan;
%find index to first column with actual values (not nan):
col = zeros(length(plot_separator),1);
use_col = zeros(length(plot_separator),1);
for i=1:length(plot_separator)
    if all(isnan(y_plot_mean(i,:)))==0;
        col(i) = find(sum(~isnan(y_plot_mean(i,:)),1) > 0, 1 ,'first');
        use_col(i) = 1; %only rows that are not empty will be used  
    end
end
figure('visible','on');  
plot_set=zeros(length(plot_separator),1);
legend_cell=cell(length(plot_separator),1);
for i=1:length(plot_separator)
    if use_col(i)==1
        plot_set(i,1)=errorbar(x_plot(1,col(i):end),y_plot_mean(i,col(i):end),y_plot_std(i,col(i):end));
        set(plot_set(i,1),'Marker',markers(i));
        legend_cell{i,1}={['/Phi=' num2str(plot_separator(i))]};
        legend_cell{i,1}=num2str(cell2mat(legend_cell{i,1}));
        hold all;
    end
end
legend(legend_cell{2:4});
xlabel('Spark Advance (CAD BTC)'); 
ylabel('Throttle (%)');