automating script using uiload

I have multiple .mat (8760x4 table) files which I want to do the same analysis on, one at a time. The script I've written works well with one of these .mat files, the one I used when I wrote the script. However, now I want to be able to use the script with all my .mat

This is what the code looks like now.

load('examplefile') %imports abc table to the workspace

xsource=linspace(datenum('01/01/14 00:00','dd/mm/yy HH:MM'),datenum('31/12/14 23:00','dd/mm/yy HH:MM'),8760); %creates a vector with datnum to use as x-axis
frb=abc.Vrde;           %Gets column Vrde from table abc
qual=zeros(length(frb),1);      %creates a vector with zeros with the same length as frb

ts=timeseries(frb,xsource,qual);     %creates a timeseries with frb,xsource,qual
ts.QualityInfo.Code= [0 1 2 3 4 5];      %different quality flags
ts.QualityInfo.Description= {'A' 'B' 'C' 'D' 'E' 'F' }; % Display name of the quality flags

When I run the script, I want Matlab to ask me which file to load. In order to do so I used uiload. This lets me chose which ever .mat file I want to perform the analysis on. This loads a table into the workspace, and it is at this point I get stuck. There is probably an easy way but I can't really see it.

Every .mat file has the same structure, So what I need to automate is creating the

frb=abc.Vrde

But with instead of abc I want to use the name of the table that was loaded using uiload. The rest of the script is based on the timeseries ts.

Is there any way to work around this?

[Kirby Fears]

Is the issue that you have a collection of .mat files that each have analogous data in the "abc" table, but the name of "abc" is different within each .mat file?

You need to know something about the name in order to make this work. Is your table "abc" the only thing in each .mat file? Otherwise, do you have a way to identify the table, such as a naming convention?

E.g. is abc always called ['results_',datestr] ?

[jakob ekwall]

Each .mat file has a name, such as abc.mat, in that .mat file there is a table with the same name. (The table is the only thing in the .mat file)

I'll add a picture to clarify.

(In this case the table in Lagzon.mat is called Lagzon)

Answer 1

[Kirby Fears]

jakob,

You can get the variables loaded in your workspace with the who command.

Try out this example:

m2 = magic(2);
m3 = magic(3);
myVars = who;

In case your workspace already has several variables, you can directly get the variable names inside your .mat file like this:

myVars = who('-file','mydata.mat');

Now myVars contains the variables names inside of mydata.mat.

Assuming you have a way of identifying the right variable name from within myVars, you can extract Vrde like this:

myColumn = eval([myVars{someIndex},'.Vrde']);

[Kirby Fears]

Here's a bit of code that should help:

[fileName,filePath] = uigetfile('*.mat'); % dialogue to choose mat file
if fileName == 0,
    warning('No file selected.');
else
    varNames = who('-file',[filePath,fileName]);
    % Insert code to determine index of the varName you want
    index = 1; % for example
    load([filePath,fileName],varNames{index}); % load only desired variable from selected file
    myColumn = eval([varNames{index},'.Vrde']); % extract column
    % Perform your analysis
end

[jakob ekwall]

This worked great! Thank you very much.

However it was a bit complicated for something that in my mind felt like an easy task.

I guess it would have been much easier if I had just given every table the same name when I made the .mat files instead of giving them all unique names.

[Kirby Fears]

Yeah, naming the tables the same would be a lot easier. The code could be simplified under the assumption that the table name is the same as the file name, but you might as well use this more general approach in case that changes later.

Cheers.

Answer 2

[Steven Lord]

Inside a function I would ALWAYS call LOAD with an output argument.

 data = load('mymatfile.mat');
 listOfVariablesFromMatfile = fieldnames(data);
 firstVariable = data.(listOfVariablesFromMatfile{1});

The third line uses a dynamic field name.