Include legends based on column names in for loop

Hi,

I have a loop which processes three tables. Each table has ten columns (in addition, each column includes column names). When I plot the three figures in the loop, I want to include legends which state the column name of each variable within the plot. I know how to make this manually by typing the legends in the Matlab code. However, since the column names are changing depending on table I want to perform this automatically in the script. My though is to use "Display" but I do not know how to apply this kind of approach. In terms of code procedure, I thought something similar to this (not working unfortunately):

vnames=Table_.Properties.VariableNames;

for v = 1:numTables

    %Processing of the code
    
    plot(Table_.Col1,Table_{:,3},'DisplayName',vnames(v))
    legend show
end

Grateful for any advice.

[Vlatko Milic]

Thank you! I made some changes to the code and now it works for several tables.

All the best

Answer 1

[KSSV]

id = (1:10)' ; 
x = rand(10,1) ;
y = rand(10,1) ;
z = rand(10,1) ; 
T = table(id,x,y,z) 

T = 10×4 table
    id       x           y           z    
    __    ________    ________    ________

     1     0.60378     0.39943    0.005615
     2    0.039465      0.2604     0.33861
     3     0.24765     0.47166     0.71508
     4     0.33116    0.064591    0.014081
     5     0.87429     0.19372      0.8671
     6     0.80526     0.74176     0.52277
     7     0.61993     0.51138     0.34342
     8     0.37336     0.11143      0.9837
     9     0.73479     0.22456     0.58077
    10     0.14989     0.96124      0.2604

figure
hold on
for i = 2:4
    plot(T.(1),T.(i),'DisplayName',T.Properties.VariableNames{i})
end
legend

Answer 2

[Mathieu NOE]

hello

see my little demo below to use the table varibales names as legend

the csv data file is attached

clearvars
clc

%get the data from table
T = readtable('pH_Data.csv'); %Reads Table or CSV File

vnames=T.Properties.VariableNames; % {'DateAndTimeRun1'}    {'Time_s_Run1'}    {'Voltage_mV_Run1'}    {'pHRun1'}
time = T.Time_s_Run1; % time (s)
data = table2array(T(:,3:end)); % data 
plot(time,data);
lgstr = vnames(3:end); % use vnames to make legend strings
% legend strings convert underscore to blanks for better legend readability
for ck = 1:numel(lgstr)
    tmp = char(lgstr(ck));
    ind = strfind(tmp,'_');
    tmp(ind) = ' ';
    lgstr{ck} = tmp; % update
end

legend(lgstr);

[Vlatko Milic]

Thank u! I went by the code above since it was was a bit shorter. I tried your code also and it works perfectly also.

All the best!

[Vlatko Milic]

Hi again, Mathieu.

I'm working with another example in which I want to implement my code. However, it is a bit more complex than your example. I have a table with 12 columns. Each column has a unique id namn consisting of both numbers and characters. II have a loop where I'm plotting this data where three of the columns are plotted in the same plot which gives 4 plots. I want to include legends based on the variable names (uniques id:s). I have problems creating this. I get the first three variables names as legends in each loop. Do you have any idea to solve this?

Thanks

[Mathieu NOE]

hello again

can you share some data and code ? I'll have a look if I get it to work !

[Vlatko Milic]

Hi, see attached file for the table I am working with. The code is as follows:

T = readtable('m.xlsx');
matchVals = {'1234', '5678','9101','1123'};
n_match = numel(matchVals);
S = struct('name',matchVals,'data',cell(1,n_match));

for k = 1:n_match
    idx = contains(T.Properties.VariableNames,matchVals{k});

    
    figure
     
 plot(1:1:10000,T{:,idx})
 
   fig_name = strcat('Box_',num2str(matchVals{k}));
  title(fig_name,'Interpreter','none') 
 
    
end

To clarify it is the variable names in the table I want as legends.

Thanks again Mathieu

[Mathieu NOE]

hello

try this :

T = readtable('m.xlsx');
matchVals = {'1234', '5678','9101','1123'};
n_match = numel(matchVals);
% S = struct('name',matchVals,'data',cell(1,n_match)); % what is this for ?
% 
vnames=T.Properties.VariableNames; % added this line

for k = 1:n_match
    idx = contains(T.Properties.VariableNames,matchVals{k});
    
    figure
     
    plot(1:1:10000,T{:,idx})
 
   fig_name = strcat('Box_',num2str(matchVals{k}));
  title(fig_name,'Interpreter','none') 
  legend(vnames(idx)); % added this line
 
    
end

[Vlatko Milic]

it works perfectly, thank you so much!

I had forgotten to remove some of the code I was working on, hence the comment in the code from my side.

Thank you!

[Mathieu NOE]

My pleasure !