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

Question

nirit 2018-10-31

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/427112-how-to-create-csv-file-with-dlmwrite-for-diffrent-vector-sizing

评论： nirit 2018-10-31

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:

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.

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Stephen23 2018-10-31

编辑：Stephen23 2018-10-31

"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.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2018-10-31

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/427112-how-to-create-csv-file-with-dlmwrite-for-diffrent-vector-sizing#answer_344360

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

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

nirit 2018-10-31

在 MATLAB Online 中打开

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);