fprintf cell array of two classes

Hi all,

I need to use fprintf to print out a char array (strictly 3 columns) and a double array side-by-side so they align. For instance:

charArr = ['USA' ; 'CAN' ; 'FRA']
doubArr = [1 2 3 4; 3 4 5 6; 6 7 8 9]

I want it to look something like:

USA 1 2 3 4

CAN 3 4 5 6

FRA 6 7 8 9

I tried to use cell arrays like below:

table = {charArr, doubArr};
fprintf( '%c, %d', table{:})

But I always get something funky and never what I want. Any help would be appreciated.

Answer 1

[Sriram Tadavarty]

Hi,

Use this if the number of rows of both the arrays are same

n = size(doubArr,1);
arrayfun(@(i) fprintf( '%s %s \n', charArr(i,:),num2str(doubArr(i,:))),1:n)

% You can even try this
comB = [charArr + " " + num2str(doubArr)];
fprintf('%s\n', comB)

Hope this helps.

Regards,

Sriram

[Lawrence Wang]

Thanks! Your second expression with the comB part is perfect. If you don't mind could you explain how exactly you got there, I'm trying to understand.

[Sriram Tadavarty]

Sure Lawrence.

It need to print the combination of numbers and characters. Since, the number of rows in both are same, the general apporach is to concatenate both the variables charArr and doubArr, like [charArr doubArr] but this converts the numeric values to the respective ASCII values. So inorder to make it combined through characters, i converted the numeric value to string value through num2str(doubArr), and then in the output you need additional space between the two arrays and each array needs to print a new line. So, comes the usage of " " in the comB variable and \n operator in fprintf respectively.

Hope this helps.

Answer 2

[Stephen23]

No need for complex strings, ugly loops, or slow arrayfun, you just need one simple fprintf call::

>> A = ['USA' ; 'CAN' ; 'FRA'];
>> B = [1 2 3 4; 3 4 5 6; 6 7 8 9];
>> C = [cellstr(A),num2cell(B)].'; % transpose to get correct order
>> fprintf('%s %d %d %d %d\n', C{:})
USA 1 2 3 4
CAN 3 4 5 6
FRA 6 7 8 9

If you want to learn how to use MATLAB efficiently, you might as well start now.

[Lawrence Wang]

Hi, thanks for you answer. I agree this is much more efficient and it works very well for this instance, however when I try to extend it to other double arrays the output isn't perfectly aligned

For example:

charArr = ['USA' ; 'CAN' ; 'FRA'];
doubArr = [ 1 0 12 3; 9 12 11 21; 2 5 9 2];

C = [cellstr(charArr),num2cell(doubArr)].';
fprintf( '%s %d %d %d %d\n', C{:})

USA 1 0 12 3
CAN 9 12 11 21
FRA 2 5 9 2

Is there any way to rectify this?

[Stephen23]

"Is there any way to rectify this? "

Of course! Just select a suitable fieldwidth, e.g.:

>> A = ['USA' ; 'CAN' ; 'FRA'];
>> B = [1,0,12,3;9,12,11,21;2,5,9,2];
>> C = [cellstr(A),num2cell(B)].';
>> fprintf('%5s %3d %3d %3d %3d\n', C{:})
  USA   1   0  12   3
  CAN   9  12  11  21
  FRA   2   5   9   2

The fprintf documentation explains the fprintf options.

[Lawrence Wang]

Oh man I can't believe I forgot that. I'll definitely brush up on the docs. Thanks so much for your help.

Answer 3

[Bhaskar R]

require = string(cell2mat(strcat(charArr,{' '}, num2str(doubArr))));