Strange file output while using fprintf

Question

Hissam Aziz 2013-4-3

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/69610-strange-file-output-while-using-fprintf

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

Hi Everyone, thank you in advance for your help. I'm trying to write two columns in a txt file using fprintf.

fprintf(filesave2,'%d %\r\n', X, Y);

I even tried manipulating the numbers of characters i wanted to print:

fprintf(filesave2,'%3d %7.5f\r\n', X, Y);

but all in vain. It keeps giving me very strange results.

Results:

9.00000
9.00000
9.00000
..... and so on.

My original data

looks like this:

X is a vector from 5 to 300 with intervals of 5. i.e. 5 10 15 ... 300

Y is a vector with power values 0.46957 0.41538 0.37951 .. etc (60 values).

How can i fix this? So that the written file looks like:

5 0.46957
10 0.41538
15 0.37951
...
etc

Thank you so much for your help!

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Answer 1

Walter Roberson 2013-4-3

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https://ww2.mathworks.cn/matlabcentral/answers/69610-strange-file-output-while-using-fprintf#answer_80812

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fprintf(filesave2,'%d %f\r\n', [X(:), Y(:)].' );

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Walter Roberson 2013-4-3

编辑：Walter Roberson 2013-4-3

在 MATLAB Online 中打开

Please re-check that X and Y have exactly the same number of elements. Whether they are row vectors or column vectors or matrices does not matter for the code I gave, as long as the number of them is the same.

The .' is matrix transpose. The first part, [X(:), Y(:)] is forming an array of two columns, X and Y, and the .' flips that around so that X becomes the first row and Y becomes the second row. You need to do this for your fprintf() because fprintf() follows values down the columns -- so you want the first column to have an X value and then a Y value (to print them side by side), and the next column to have the second X and Y values, and so on.

If you knew for sure that X and Y are row vectors, then you could instead have coded as

fprintf(filesave2,'%d %f\r\n', [X;Y] );

Hissam Aziz 2013-4-3