How to write data in an appointed data format?

Question

Kathleen 2016-2-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/268506-how-to-write-data-in-an-appointed-data-format

评论： Star Strider 2016-2-17

采纳的回答： Star Strider

在 MATLAB Online 中打开

Dear colleagues,

I have a column data:

44566

44567

44568

44565

44566

4565

44563

99999

44561

44563

44564

...

but I want to convert my data into the following data format, e.g., 6f12.4 would imply six values per row each twelve characters long with four decimal places.

4565.000 44566.000 44567.000 44568.000 44565.000 44566.000

4565.000 44563.000 99999.000 44561.000 44563.000 44564.000

.....

Could you give me some good suggestions? Many thanks!

3 个评论
显示 1更早的评论隐藏 1更早的评论

Kathleen 2016-2-17

编辑：Kathleen 2016-2-17

Thanks for your comment! "Twelve characters" is Fortran format such as 6f12.4. No, I also have the real numbers.

Could you give me some advices and help?

Star Strider 2016-2-17

在 MATLAB Online 中打开

My pleasure!

It works essentially the same way in MATLAB, but the format is more like C than FORTRAN, even though MATLAB began as FORTRAN-based. For details on the various format descriptors, see the documentation for the fprintf function.

To do the equivalent of 6F12.4 in FORTRAN with the ‘newline’ characters as well, in MATLAB it’s useful to use the repmat function. For instance, your format and print statements would be:

fmt = [repmat('%12.4f\t', 1, 5) '%12.4f\n'];
fprintf(fid, fmt, v);

I broke these out into two lines to (1) demonstrate that it is possible, and (2) demonstrate alternate ways to repeat format descriptors in MATLAB.

The tab characters ('\t') are necessary in MATLAB if you want to read the file easily, because one shortcoming in MATLAB file read capability is the inability to specify precise column field widths, so a line such as:

3.1415E+005-1.2345E-010

completely eludes MATLAB, and requires special reading and parsing to eventually dissect it into 3.1415E+005 and -1.2345E-010 that would be easily read in FORTRAN. May be someday MATLAB will have that capability built-in.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Star Strider 2016-2-17

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/268506-how-to-write-data-in-an-appointed-data-format#answer_210102

在 MATLAB Online 中打开

It would imply that in FORTRAN but not MATLAB.

You would have to do something like this:

v = [44566
    44567
    44568
    44565
    44566
    4565
    44563
    99999
    44561
    44563
    44564
    44567];
fid = 1;                                    % Here ‘1’ Is ‘stdout’, The Command Window, But You Would Use The ‘fopen’ Function To Write To A File
fprintf(fid, '%12.4f\t%12.4f\t%12.4f\t%12.4f\t%12.4f\t%12.4f\n', v)

producing:

    44566.0000    44567.0000    44568.0000    44565.0000    44566.0000     4565.0000
    44563.0000    99999.0000    44561.0000    44563.0000    44564.0000    44567.0000