How do I put spaces before a line in a txt file using strcat and fprintf?

Question

Ali Almakhmari 2023-4-16

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1948033-how-do-i-put-spaces-before-a-line-in-a-txt-file-using-strcat-and-fprintf

编辑： Image Analyst 2023-4-16

When I go in MATLAB and try to print ' 1,2,3' in the file opened in fid_wrt as shown below. I will find that the file has '1,2,3', without the spaces.

B{1} = '%.4f,%.4f,%.4f';
fprintf(fid_wrt,strcat('   \n',B{1},','),1:1:3);

I tried adding the spaces before \n...after it...nothing. I just can't get those spaces in the fid_wrt file. I just want those spaces before the numbers man. Whats weird is that fprintf (without writing in the file) does show those spaces in the command window!!

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Stephen23 2023-4-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1948033-how-do-i-put-spaces-before-a-line-in-a-txt-file-using-strcat-and-fprintf#answer_1216643

在 MATLAB Online 中打开

STRCAT removes whitespace characters. The easy and robust approach is separate FPRINTF calls:

fprintf(fid_wrt,'   \n')
fprintf(fid_wrt,B{1},1:1:3)
fprintf(fid_wrt,',')

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Image Analyst 2023-4-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1948033-how-do-i-put-spaces-before-a-line-in-a-txt-file-using-strcat-and-fprintf#answer_1216588

在 MATLAB Online 中打开

strcat does an automatic trim of spaces. Just use fprintf alone. No need for B or strcat.

 % Have a line with spaces on it before the line with numbers on it.
 fprintf(fid_wrt,'   \n%.4f, %.4f, %.4f\n', 1 : 3);

2 个评论
显示无隐藏无

Ali Almakhmari 2023-4-16

The thing is, B{1} changes in the code...its not something that is a constant. So I need strcat to concatenate B{1} in the fprintf.

Image Analyst 2023-4-16

编辑：Image Analyst 2023-4-16

在 MATLAB Online 中打开

You could put B in as a string

% Define a format specifier string using B.
B{1} = '    \n%.4f,%.4f,%.4f\n';
formatSpecifier = B{1};
% Have a line with spaces on it before the line with numbers on it.
fprintf(fid_wrt, formatSpecifier, 1 : 3);