How fprintf cell array and martix?

I want to fprintf a cell array and a matrix to a txt file. I used the following code, but got the wrong result.

 xx={'2017032312_8953';'2017032312_8978'};

 yy=[10;11];

 fprintf('%s %e \n ',xx{:}, yy)

The results is:

 2017032312_8953 5.000000e+01 
 017032312_8978 1.000000e+01

I want the result like this:

 2017032312_8953 1.0E+01 
 2017032312_8978 1.1e+01

How can this problem be solved? Many thanks!

Answer 1

[per isakson]

xx={'2017032312_8953';'2017032312_8978'};
yy=[10;11];
for jj = 1 : length( xx )
    fprintf( '%s %3.1E \n', xx{jj}, yy(jj) )
end

outputs

2017032312_8953 1.0E+01 
2017032312_8978 1.1E+01

Comparison of elapse times of loop codes and the vectorized code by Stephen Cobeldick

"It is better, since my data is huge." "Huge" implies that you want to write to a text file.

Here is a test on R2016a 64bit, Win7 and an old vanilla desktop.

>> et = cssm(1e4)
et =
    8.4265    0.6577    0.1814

The difference between the first and the second elapse time value illustrates the influence of automatic flushing on speed. (Both are based on for-loops.) See Improving fwrite performance at Undocumented Matlab by Yair Altman. The third value is the elapse time of the vectorized code by Stephen Cobeldick.

The test is done with this function

function    et = cssm(N)
    xx = repmat( {'2017032312_8953';'2017032312_8978'}, N,1 );
    yy = repmat( [10;11], N, 1 );
tic
    fid = fopen( 'test1.txt', 'w' );
    for jj = 1 : length( xx )
        fprintf( fid, '%s %3.1E \n', xx{jj}, yy(jj) );
    end
    fclose( fid );
et = toc;
tic
    fid = fopen( 'test2.txt', 'W' );
    for jj = 1 : length( xx )
        fprintf( fid, '%s %3.1E \n', xx{jj}, yy(jj) );
    end
    fclose( fid );
et(end+1) = toc;
tic
    C = xx.';
    C(2,:) = num2cell(yy);
    fid = fopen( 'test3.txt', 'W' );
    fprintf( fid, '%s %3.1E \n', C{:});
    fclose( fid );
et(end+1) = toc;    
end

[Qingsheng Bai]

Thanks! This helped me a lot.

[per isakson]

I added a speed test to my answer.

Answer 2

[Stephen23]

Avoiding the for loop is quite easy too:

C = xx.';
C(2,:) = num2cell(yy);
fprintf('%s %3.1E \n', C{:})

which prints:

2017032312_8953 1.0E+01
2017032312_8978 1.1E+01

[Qingsheng Bai]

Thank you. It is better, since my data is huge.

[Stephen23]

@Qingsheng Bai: I hope that it helps. You can also vote for my answer if it was useful for you.