Importing multiple excel sheet's data into individual variables

Very similar to this question, I want to import multiple columns from multiple excel sheets and create a column vector with a name based on the input file. What I've managed to do so far is import all of one variable from all sheets into one array, but I want them separately.

source_dir ='E:\xxxx'
source_files = dir(fullfile(source_dir,'*.csv'));

for k=1:length(source_files) 
    d{k} = xlsread(fullfile(source_dir,source_files(k).name), 'A:A'); %distance upstream
    e{k} = xlsread(fullfile(source_dir,source_files(k).name), 'D:D'); %elevation upstream
    x{k} = xlsread(fullfile(source_dir,source_files(k).name), 'B:B'); %x co-ord
    y{k} = xlsread(fullfile(source_dir,source_files(k).name), 'C:C'); %y co-ord
    a{k} = xlsread(fullfile(source_dir,source_files(k).name), 'E:E'); %upstream area
    s{k} = xlsread(fullfile(source_dir,source_files(k).name), 'F:F'); %local slope

end

I'd want outputs of d111, e111, x111 etc, where 111 is the file name.

Answer 1

[Hannes Daepp]

As I understand, you would like to have separate variables for each entry, rather than storing them in the cell arrays as you have done above, and you would like those variables to be automatically generated based on the name of the input file.

You can do this using the "eval" command, though it is generally discouraged because it's inefficient and can be difficult to debug. That issue is elaborated upon in this past Answers post: https://www.mathworks.com/matlabcentral/answers/143-how-do-i-make-a-series-of-variables-a1-a2-a3-a10

For example, you could instead generate fields of a structure and populate that:

>> varname = matlab.lang.makeValidName(source_files(k).name(1:end-4));
>> myData.(varname) = xlsread(fullfile(source_dir,source_files(k).name), 'A:A');

The first line is to ensure that you define allowable variable names: http://www.mathworks.com/help/matlab/ref/matlab.lang.makevalidname.html

If you are set on automatic variable generation, you could do that using "eval":

>> varname = matlab.lang.makeValidName(source_files(k).name(1:end-4));
>> eval([varname '= xlsread(fullfile(cd, source_dir,source_files(k).name),'...
        char(39) 'A:A' char(39) ');']);

However, as noted above, I would encourage you to explore other options. You may find the following documentation to provide some useful suggestions: http://www.mathworks.com/help/matlab/matlab_prog/string-evaluation.html