Code section clarification - function

Hi everyone,

I am quite new to matlab, but I have some background knowlege in python and java.

I have been given this code to analyse and i am struggling to understand section 3 and 4. If anyone could tell me what those section do, i would greatly appreciate it.

This code is for analysing UV-VIS data ( x,y) = ( wavelenght , absorption) for a region between 400 - 800 nm. I believe section 3 doesnt need "for" and "end "syntax.

Many thanks for your help

function  Analyse_UV( ConcnVector )
 %  Analyse_UV
 %  Function loads UV/Vis data, finds SPR band, fits model gaussian 
 %  function to it using an evolutionary algorithm, and prepares the data
 %  for calculation of fwhm.
 
 %% USER INPUTS
 % 1) Save the csv file containing the UV/Vis data as 'data.csv'.
 % 2) Create a vector (ConcnVector) e.g. [1 2 3 4 ...] containing the
 % concentration values of the titrate (in uM).
 % 3) If last dataset is of purified nanoparticles, the code reports the
 % new NP concentration based on the input argument 'NPConc'.
 % 3) Label the titrate for 'xlabel' in Section 8
 
close all
clc
%% NP CONCENTRATION

NPConc = 20;
    
 %% 1) Import data file, and sort into headings and data
[NUM,TXT,NAW] = xlsread('Test1.xls');
ConcnVector = ConcnVector';
    
for i=1:1:length(ConcnVector);
    legend2{i}=num2str(ConcnVector(i))';
end

 %% 2) Acquire Dimensions & Resize
dim=size(NUM);
imax=(dim(1,2));

%% 3) Import Headings
for
    i=1:2:imax
    headings0(i)=[TXT(1,i)];
end

headings=headings0';
headings(cellfun(@isempty,headings))=[]; % delete empty entries

%% 4) Normalise Spectra to First Measurement
% Algorithm assumes first measurement is AuNPs. It then normalises all
% measurements to this measurement.
NcolNUM = size(NUM,2);
if NcolNUM >2
    NUM2 = zeros(size(NUM,1),size(NUM,2));
    LOWER = NUM(1,2);
    for i=1:2:imax
        UPPER = NUM(1,i+1);
        NUM2(:,i+1) = NUM(:,i+1)-(UPPER-LOWER);
        NUM2(:,i) = NUM(:,i);
    end
end
NUM = NUM2;

%% 5) Run UV/Vis Analysis
SetSize = 0.5*size(NUM,2);
Results = zeros(SetSize,3); % zeros returns a 0 values array boxes
PlotNum = ceil(SetSize*0.5);
Set = 1;
figure;
hold all
for i=1:2:imax
    y = NUM(:,i:i+1);
   [SPR, FWHM, lmerr, xdataf, ydataf,SPRBandf] = Average_UV_13nm(y);
   Results(((i+1)/2),1) = SPR;
   Results(((i+1)/2),2) = FWHM;
   Results(((i+1)/2),3) = lmerr;
   
   subplot(2,PlotNum,Set);
   plot(xdataf,ydataf,'-','linewidth',1.5);
   hold on
   plot(xdataf,SPRBandf,'--','linewidth',1.5);
   title(headings((i+1)*0.5), 'FontSize',12);
   xlim([450 620])
   Set = Set+1;
   j = (i+1)/2;
   Abs(j) = max(SPRBandf);
   if i == imax-3
       IniAbs = max(SPRBandf); %Report SPR height before purification
   end
   if i == imax-1
       FinAbs = max(SPRBandf); %Report SPR height after purification
   end  
   xlim([400 650]);
end
% 
% ConcRatio = FinAbs/IniAbs;
% New_Concentration_in_nM = ConcRatio*NPConc %Calculate new NP conc in nM
% DilutionCalc=(New_Concentration_in_nM, 0.5, 3000)
% hold off

%% 6) Sample Data Plot
%Plots last studied dataset & SPR fit
figure;
plot(xdataf,ydataf,'-','linewidth',1.5);
hold on
plot(xdataf,SPRBandf,'--','linewidth',2);
title('Example of UV/Vis Data with SPR Fit', 'FontSize',18);
xlabel('\lambda /nm', 'FontSize',16);
ylabel('Absorbance', 'FontSize',16);
% LEG=legend('UV/Vis Data','Levenberg-Marquandt fitting of SPR band');
SampleHeadings = {'UV/Vis Data','Levenberg-Marquandt fitting of SPR band'};
legend(SampleHeadings,'FontSize',16,'Location','NorthEast');
set(gca,'FontSize',13)
%LEG = findobj(AX,'type','text');
%set(LEG,'FontSize',14)

%% 7) Plot all UV/Vis Data
% N. B>  - Title graph below
L = length(NUM);
figure;
for i=2:2:imax 
    hold all;
    axis([400 800 0 2.2]) % Axis Lengths
    plot(double(NUM(1:L,1)),double(NUM(1:L,i)),'linewidth',2);
    set(gca, 'XTick', 0:50:800, 'FontSize',12);   
end
Last = NUM(:,end);
JJJ = max(Last(1:350))*1.2;
axis([400 800 0 JJJ]) % Axis Lengths
legend(headings,'FontSize',13,'Location','SouthWest');
title('UV/Vis Absorption of Au^1^3NPs', 'FontSize',18); % More appropriate title required
xlabel('\lambda /nm', 'FontSize',20);
ylabel('Absorbance', 'FontSize',20);

figure;
uitable('Data', Results, 'ColumnName', {'SPR', 'FWHM', 'lmerr'},'RowName', headings,'Position', [20 20 1000 400]);

%% 8) Plot SPR & FWHM Data

SPR = Results(:,1);
SPR = SPR(:,1)-SPR(1,1);
FWHM = abs(Results(:,2));
FWHM = FWHM(:,1)-FWHM(1,1);

figure;
plot(ConcnVector,SPR,'--o','linewidth',2,'markers',9);
hold on
plot(ConcnVector,FWHM,'--*','linewidth',2,'markers',9);
axis auto
set(gca,'FontSize',13)
xlim([ConcnVector(1),ConcnVector(end)+1]);
ylim([0,SPR(end)+2]);
xlabel('Concentration of pHLIP/ \muM', 'FontSize',18); %% User Input Required %%
ylabel('\Delta\lambda /nm', 'FontSize',18);
SPR_Headings = {'Surface Plasmon Resonance \lambda_m_a_x','Full Width at Half Maximum'};
legend(SPR_Headings,'FontSize',13,'Location','NorthEast');

figure;
MaxAbs = max(Abs)*1.2;
MinAbs = min(Abs)*0.8;
[haxes,hline1,hline2] = plotyy(ConcnVector,SPR,ConcnVector,Abs);
set(hline1,'linewidth',1.5);
set(hline2,'linewidth',1.5);
set(haxes(2),'YLim',[MinAbs MaxAbs]); %MinAbs MaxAbs %adjust axes here!!!
set(haxes(2), 'YTick', MinAbs:0.2:MaxAbs, 'FontSize',13); %adjust axes here!!!
set(haxes(1),'YLim',[0 SPR(end)+2]);
set(haxes(1), 'YTick', 0:1:SPR(end)+4, 'FontSize',13); 
ylabel(haxes(1),'\Delta\lambda /nm', 'FontSize',18); % left y-axis
ylabel(haxes(2),'Absorbance', 'FontSize',18) % right y-axis
xlim([ConcnVector(1),ConcnVector(end)+1]);
set(hline1,'Marker','o','MarkerSize',9);
set(hline1,'LineStyle','--');
set(hline2,'Marker','+','MarkerSize',9);
set(hline2,'LineStyle','--');


hold on
hline3 = plot(ConcnVector,FWHM,'-');
set(hline3,'linewidth',1.5);
set(hline3,'Marker','*','MarkerSize',9);
set(hline3,'LineStyle','--');
SPR_Headings2 = {'Surface Plasmon Resonance \lambda_m_a_x','Full Width at Half Maximum','Absorption'};
legend(SPR_Headings2,'FontSize',13,'Location','NorthWest');
xlabel('Concentration of EuL /\muM','FontSize',18);
set(haxes(2),'XLim',[ConcnVector(1),ConcnVector(end)+0.1]);
% 
set(haxes(1),'XLim',[ConcnVector(1),ConcnVector(end)+0.1]);
set(haxes(2),'XTick',[]) % Remove ticks of axis 2 (leaves right-hand ticks of axis 1)
set(haxes(1),'Box','off')
set(haxes(1),'FontSize',14);
xlim([ConcnVector(1),ConcnVector(end)+0.1]);
end

Answer 1

[Walter Roberson]

for
  i=1:2:imax
  headings0(i)=[TXT(1,i)];
end

The for should be the same line as the i=

You are correct that a loop is not necessary

headings0(1:2:imax) = TXT(1,1:2:imax);

Every second heading is being copied.