How to get values of selected variables from workspace?

30 views (last 30 days)
I have a huge number of signals/variables imported into workspace and I require only some selected variables along with values. Every variable is a double array. I have used string compare to get the selected variables but this gives only the names of them but not the values. I have used who which gives me only the names of the variable. Please guide me on how to get the values of each of these variables in a double array format.
load Test_2_4_1.mat;
variables = who;
%h = workspaceHandle;
%V = GetVariable(h,'variables','workspace');
%%to compare n parts of variable names (strings)
variable_list = variables;
ans = strncmpi(variable_list,'PEC',3);
ans_double = +ans;
%k = 1;
i=1;
for k = 1:size(ans_double,1)
if ans_double(k) ==1
selected_signals(i) = (variable_list(k));
%value(i) = workspaceHandle.getVariable(selected_signals(i));
i=i+1;
end
end
selected = selected_signals.';
z = evalin('base','selected');

Accepted Answer

Guillaume
Guillaume on 29 Jun 2016
Edited: Guillaume on 29 Jun 2016
The simplest way is to load your variable into a structure, simply by giving an output to load, then you can use dynamic field names to access your variables:
matcontent = load Test_2_4_1.mat;
usefield = strncmpi(fieldnames(matcontent),'PEC',3);
%instead of a loop you can then convert the structure into a cell array and simply index the cell array:
matcontent = struct2cell(matcontent);
selectedvariables = matcontent(usefield); %cell array of selected variables
Note:
  • do not use ans as a variable name. This is a name reserved by matlab. The content of ans can change at any time (any time you don't provide an output to a function).
  • avoid eval, evalin, etc. like the plague.
  • if x == 1 when x is logical (as in your case) is the same as if x. Converting x to double and then comparing to 1 is a complete waste of time.
  3 Comments
Guillaume
Guillaume on 29 Jun 2016
Before converting the structure to a cell array:
allvars = fieldnames(matcontent);
selectednames = allvars(usefield); %after usefield is created obviously.
Sachin Nag
Sachin Nag on 23 Feb 2018
Thanks a lot Guillaume. This was a very simple and helpful answer. Easy to understand and works!!

Sign in to comment.

More Answers (0)

Categories

Find more on Structures in Help Center and File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!