MATLAB: Generate numeric code based on string value

cell arraystrings

In my cell array, I have one column which contains string values such as a_abc_ABC. How can I generate a new column/ variable which assigns a number to each a_abc_ABC combination? E.g., a_abc_ABC could be 1, a_def_ABC could be 2 etc.

Best Answer

c = {'a_abc_ABC', 'a_def_ABC', 'b_def_ABC', 'a_abc_ABC', 'a_def_ABC'};
[~, ~, c_num] = unique(c);

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MATLAB: How to access a base workspace variable from within a function

This enhancement has been incorporated in Release 2006b (R2006b). For previous product releases, read below for any possible workarounds:

The EVALIN function allows you to evaluate commands in two specfied workspaces: 'base' (MATLAB's base workspace), and 'caller' (the workspace where the function was called from). In the case where the function was called from the base workspace, the two workspaces are the same. You will need to create a string that will evaluate as the proper MATLAB expression, in order to perform the assignment.

Example using EVALIN:

function myfcn(varname)
for i = 1:size(varname,1)
    if iscellstr(varname),
      evalin('base',[varname{i} ' = 'mat2str(i) ';'])
    elseif ischar(varname)
      evalin('base',[deblank(varname(i,:)) ' = 'mat2str(i) ';'])
    end
end

The ASSIGNIN function assigns values to variables in the same specified workspaces. This allows you to avoid the string conversion which is necessary with EVALIN.

Example using ASSIGNIN:

function myfcn(varname)
for i = 1:size(varname,1)
    if iscellstr(varname),
      assignin('base',varname{i},i)
    elseif ischar(varname)
      assignin('base',deblank(varname(i,:)),i)
    end
end

MATLAB: Read the size of cell array with the same element

Please use valid matlab syntax in your question, so it's not ambiguous. Assuming that your cell array is of the form:

c = {'01,jpg'  
     '01,jpg'
     '01,jpg'
     '01,jpg'
     '01,jpg'
     '01,jpg'
     '04,jpg'
     '04,jpg'
     '05,jpg'
     '05,jpg'}

This would work:

 [~, ~, id] = unique(c, 'stable');
 sequencelengths = diff(find(diff([-Inf; id; Inf])))

Best Answer

Related Solutions

MATLAB: How to access a base workspace variable from within a function

MATLAB: Read the size of cell array with the same element

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