I need to write a for loop so that my script analyses every 3rd column in my data

Hi,

Basically I have a huge amount of data, which I am writing a script for.

Essentially, i am trying to create 3 graphs per pH value at different wavelengths.

I have this so far:

Direc=dir("c:/Users/Documents") %determine directory
FileName=xlsread("Exp1FApHluorinTEST.xlsx") %determine file name
T=(0:8:1072);%vector of time from 0-1072 with 8 min interval 
Dat=[];
Ave=[]
j=1;
[rows,cols]=size(FileName);

I have a data set which looks like this, I know it's a lot, sorry

Essentially, I want to create a graph, I know how to do this, but I do not know how to create a for/if loop to take all the information from 395nm for the entire dataset at each timepoint, and for each condition.

There are 135 readings for each wavelength, and essentially the conditions are tested in triplicate, so I have a rough code of what I used previously which is:

for i=1:cols;
    if mod(i,2)==0;
    Dat(:,j)=FileName(:,i);
    j=j+1;
    end
end
for j=1:(cols/2)
    
    for i=1:(rows/3)
        Ave(i,j)=mean([Dat((3*i-2),j) Dat((3*i-1),j) Dat((3*i),j) ]); 
    end
end

Though this is for a different data set where I required only the use of every other column, and then averaging of the 3 rows across that column, now I need every column.

If this makes sense, could someone please help me.

Thank you

[dpb]

1. Attach a portion of the file people can see to do something with -- I can't begin to even read that image.
2. Use readtable to make a table--_much_ more handy to pick data from by variable name instead of just positions (presuming the headings which I can't read are different variables).
3. See ismember() to select subsets or use findgroups to process by criteria of choice.

But, first and foremost, attach the data and clarify just what it is you want to be able to do.

[Fope Ayo]

I can't attach a portion of the file, only the full file.

I have attached it below.

I don't know what readtable or ismember is and would prefer not to use it as I have a template code, I just need it altered a bit.

I have clarified what I want it to be able to do.

I want to create 3 graphs per pH value, there are 8 pH points, so its a graph of time against absorbance.

There are 3 absorbance values - 395, 375 and 322.

The data is tested in triplicate, going vertically down the well rows A01,A02,A03 is under one pH point for one condition, B01,B02,B03, is under a different pH point for that same condition.

Therefore I need to create 3 graphs per pH point.

So for 395, I need 4 plots on that one graph, one for the average of the data from A01-A03, one for the average of the data from A04-A06, and so on up and till 12. That produces one graph for the first pH point.

Does this make sense?

[dpb]

"I can't attach a portion of the file, only the full file."

Of course you could have...just save a portion as a new file and post it. But, ok...having data is the important thing.

[Fope Ayo]

I didn't think it would be useful to do that because you require the whole data set to write the code.

Nevertheless, I have attached a sample if that is more useful

I appreciate the tips, but there has been no actual help on the code, just comments on how I have phrased the question.

[dpb]

Well, we gots to figure out what the problem is before we can write code...and they were "just comments" and no, one doesn't have to have the whole file to write the code...only enough to be able to understand the data structure, specifically.

[dpb]

OK, I see the file -- still not completely clear on who's to get plotted on a single axis--are you saying to average by the Group Variable ('A','B',...) or by the combination of Well and Group?

Then for whichever is averaging over, plot the data for all the 395, 475, 322 wavelengths each on separate plot?

What's the abscissa, just ordinal number or the timestamp buried in the Time column?

[Fope Ayo]

Average by the Group, sorry this is easier to understand.

Plot the average data 395 for the first 3 which is AAA, then plot the average data at 395 for the next set of AAA, so essentially missing out the other groups - B, C and D on 8 different plots as the groups correspond to pH.

Sorry, I am not aware of what an abscissa is, probably the timestamp buried in the Time column.

[dpb]

I got pulled away on farm activities (the cows have to drink), sorry... :)

So, to see if I got this, you're looking for 8 plots versus time with each of the four groups of three for a given group averaged over the repetitions?

Are the three wavelengths parameterized on each plot or are there then 8*3==>24 plots in total?