print numbers in Enginering Notation

Hi everyone,

I need to print out in a txt file a list of numbers, one for each row, with this format:

i.dddddddddddddde+000 hence 1digit before decimal separator, 14 after that and 3 for the exponent.

Could anyone help me?

Thanks,

Stefano

[Harry Coules]

If your list of numbers is a vector A, for example:

>> A = [pi;20*pi;300*pi;4000*pi;50000*pi]
A =
     1.0e+05 *
      0.0000
      0.0006
      0.0094
      0.1257
      1.5708

The following code will write a text file in the current directory in an output format similar to that which you specified, but with only 2 digits for the exponent:

    fileID = fopen('filename.txt','w','n','UTF-8');
    formatSpec = '%1.14e\n';
    fprintf(fileID,formatSpec,A);
    fclose(fileID);

I don't know if there's a 'clean' way to do three digits for the exponent... Does anyone else know?

Regards, Harry

[dpb]

Only if the actual field exponent is 3-digit in length will the C i/o formatting library display the third decimal. AFAIK this is C Standard behavior in that there's no formatting string option to specify the width of the exponent field.

Answer 1

[Jos (10584)]

Separate the mantissa and the exponent

   Values = [pi ; 1.12301230123e17 ; 100000 ; 9999999999999]
   E = floor(log10(Values))  % exponent
   M = Values ./ (10.^E)     % mantissa
   TMP = [M(:) E(:)].'
   fprintf('%1.14fe%03d\n', TMP)

Answer 2

[Stefano]

thank you guys!