Iterate through alphabetical names

Hello there,

maybe it's a dumb question, but how do I iterate through alphabetical names? Assuming I have matrices A to D, then how can I use those names in a loop?

My approach would be to create a string

 names='ABCD'

and loop through those in a loop

 for i=0:4
  names(i)
 end for

But how can I use this for example for the following operation?

 boxplot(A(:))

If I simply use

 names='ABCD';
 for i=0:4
  boxplot(name(i)(:))
 end for

Then it doesn't work, of course. strcat does not do the job either.

I hope someone has an idea :)

Cheers

Answer 1

[Star Strider]

Not dumb at all.

You need to use the eval function in your loop:

A = rand(2,10);
B = rand(3,10);
C = rand(4,10);
D = rand(5,10);

names = 'ABCD';

for k1 = 1:length(names)
    figure(k1)
    boxplot(eval(names(k1)))
end

Answer 2

[Marc]

That's great, thank you!

[Star Strider]

My pleasure!

Answer 3

[Marc]

Okay one more question ... how can I access a variable using a predefined name vector?

 for i=1:length(models)
    fprintf('\t Open %s\n', models{i})
    eval(models(i))=xlsread(strcat(path,'\',eval(models(i)),'_PER.xlsx'));
 end

Eval does not do the job here ?

[Star Strider]

If you already have a predefined variable name, simply use it:

   for i=1:length(models)
      fprintf('\t Open %s\n', models{i})
      models(i)=xlsread(strcat(path,'\',eval(models(i)),'_PER.xlsx'));
   end

However you will probably need to add dimensions to it to put the xlsread data into it:

   for i=1:length(models)
      fprintf('\t Open %s\n', models{i})
      models(i,:,:)=xlsread(strcat(path,'\',eval(models(i)),'_PER.xlsx'));
   end

Just guessing here, since I have no idea what ‘models’ is, what it contains, or that the various xls arrays are the same size (although I assume here that they are).

[Marc]

My bad ... models is the vector containing the names. Using models{i} puts the files into models ... not exactly what I need :D using models(i) doesn't work. Using eval( )= doesn't work either no matter what I place within the brackets.

path=''; fprintf('Path: %s\n', path)

 models={
    '102030'
    '30SR'
    '30WHS1'
    '30WHS2'
    '40'
    '4550'
    '51'
    '556077'
    '200210220'
    '230240'};

 fprintf('Open Excel sheets:\n')

 for i=1:length(models)
    fprintf('\t Open %s\n', models{i})
    xlsread(strcat(path,'\',models{i},'_PER.xlsx'));
 end

[Marc]

Okay - in the meantime I switched to use structs instead of regular variables ... I thought too much in common programming languages ;)

[Star Strider]

See if evalin will do what you want.