How to create a for loop to go through data arrays?

I am trying to plot a bunch of arrays that I have in a 1x1 structure, labelled data, with 178 fields. The fields are named "laser1", "laser2", ....., "laser178".

Within each field I have 2 fields/separate data arrays (of which I am only interested in the one labelled pulse). I am trying to plot all these data arrays, which if done one by one would require me to do

plot(data.laser1.pulse)
hold on
plot(data.laser2.pulse)
hold on

This can probably be quite easily solved using a for loop but I don't seem to be able to do so. I tried doing the following:

data = load('file.mat')

for x = 1:178
    a = data.laser{x}.pulse;
    plot(a)
    hold on
end

How do I incorporta the number of the variable into the name of the array I want to plot?

PS: A better way to explain my question is asking why does this not work?

for k = 1:178
    FileName=['data.laser',num2str(k), '.pulse']
    plot(FileName)
    hold on
end

I know this doesn't work because of the quotation marks (") but I don't know how to get rid of them.

Answer 1

[Chunru]

%data = load('file.mat');

data.laser1.pulse=randn(10,1);
data.laser2.pulse=randn(10,1);
data.laser3.pulse=randn(10,1);
data.apple.pulse=randn(10,1);
f = fields(data)

f = 4×1 cell array
    {'laser1'}
    {'laser2'}
    {'laser3'}
    {'apple' }

f = f(contains(f, 'laser'))  % select those containing laser

f = 3×1 cell array
    {'laser1'}
    {'laser2'}
    {'laser3'}

for i=1:length(f)
    a = data.(f{i}).pulse;
    plot(a)
    hold on
end

[Gordon]

This works if all the files are named the same, but what if I have other fields in the same array with different names?

So for example, using the same example as above, but I also had some fields labelled "Apple", "Banana", "Pear", but I still only wanted the "laser1" and so files. Will this method allow me to solely plot the desired arrays? I don't think, but perhaps I just didn't understand it (I am sorry I am quite new at this).

[Chunru]

Basically, you find all the field names and then loop through them. If you only want to loop through some of variables, for example, laser1 and so on, you can select them by pattern match. See the update above.

[Gordon]

That is perfect! Thank you so much.