how to create csv file with dlmwrite for diffrent vector sizing?

hello, I have sevral of colums vector with different sizes, and I want to write them all to a csv file,in the following way:

for example, vec1=[11,12,13,14], vec2=[21,22,23]; vec3=[31,32,33,34,35,36] the output should be something like this:

line1: 11, 21,31
line2: 12, 22,31
line3: 13, 23,32
line4: 14,   ,34
line5:   ,   ,35
line6:   ,   ,36

but instead the output is like this:

11,21,31
12,22,32
13,23,33
14,34
35
36

the code:

 vec1=[11,12,13,14]; vec2=[21,22,23]; vec3=[31,32,33,34,35,36];
 vec=[];
 for i=1:max([length(vec1),length(vec2),length(vec3)])

    if (i<=length(vec1))
        vec=[vec,vec1(i)];
    else vec=[vec,[]];
    end

     if (i<=length(vec2))
        vec=[vec,vec2(i)];
    else vec=[vec,[]];
    end

    if (i<=length(vec3))
        vec=[vec,vec3(i)];
    else vec=[vec,[]];
    end

      dlmwrite('test.csv', vec,'-append');
      vec=[];
 end

I tried replacing "vec=[vec,[]]" in the else with "vec=[vec,NaN]", and it worked, but I dont want to see "NaN" at all in the csv file. is there any other way to keep it blank? for record, I do not know in advance the length of each vector.

[Stephen23]

"is there any other way to keep it blank?"

Not they way you are trying. Numeric array must contain numeric values, and [] is not a numeric value (it is an empty array). You could write your own export function using low-level operations (i.e. fprintf).

Or just use NaN.

Answer 1

[Walter Roberson]

This is not possible using csvwrite or dlmwrite. You will need to fopen / fprintf / fclose.

[nirit]

this is what worked for me in the end:

vec1=[11,12,13,14]; vec2=[21,22,23]; vec3=[31,32,33,34,35,36];
fid = fopen('test.csv', 'w');
if fid == -1, error('Cannot open file for writing.'); end

 for i=1:max([length(vec1),length(vec2),length(vec3)])

    if (i<=length(vec1))
        fprintf(fid,'%g,',vec1(i));
    else fprintf(fid,',');
    end

     if (i<=length(vec2))
        fprintf(fid,'%g,',vec2(i));
    else fprintf(fid,',');
    end

    if (i<=length(vec3))
        fprintf(fid,'%g,',vec3(i));
    else fprintf(fid,',');
    end
      fprintf(fid,'\n');
 end
fclose(fid);

Answer 2

[madhan ravi]

instead of [] you can use 0 , you can omit it later on

 else vec=[vec,0];

[nirit]

yes, but I dont want to omit the zeros of vectors (if the contain the value 0)

[madhan ravi]

      dlmwrite('test.csv', vec,'delimiter',',','TreatAsEmpty',1,'-append');