how to automatically sprintf an array elements

Dear All,

I have many arrays with various number of columns, that is, I have many 1*m matrices with m varies from 1 to 20. For instance, consider these three hypothetical arrays:

     A1 = [1 14 20 8]
     A2 = [5 1 20]
     A3 = [2]

what I am after is creating a sprintf for each array to put together all array elements such that elements are separated by a dot. For the above examples, the desired outputs are

     1.40.20.8  % sprintf('%d.%d.%d.%d', A1(1,1), A1(1,2), A1(1,3), A1(1,4)); three dots required
     5.1.20      % sprintf('%d.%d.%d', A2(1,1), A2(1,2), A2(1,3)); two dots required
     2           % sprintf('%d', A3(1,1)); no dot required

It is certainly simpler if all of the arrays have same number of columns. But since it is not the case, I have no idea how to proceed. I just want an algorithm which automatically generates the sprintf for me with the correct number of dots.

Thanks.

Answer 1

[Stephen23]

function str = myfun(vec)
str = sprintf('.%d',vec);
str = str(2:end);
end

and tested:

>> myfun([1,14,20,8])
ans =
1.14.20.8
>> myfun([5,1,20])
ans =
5.1.20
>> myfun([2])
ans =
2

It would be great if MATLAB allowed indexing to follow a function call, as then this could be achieved in an anonymous function.

[Homayoon]

got it. my bad thanks

[Stephen23]

Since R2016b using the string class:

join(string([1,14,20,8]),".")

ans = "1.14.20.8"

join(string([5,1,20]),".")

ans = "5.1.20"

join(string([2]),".")

ans = "2"

Answer 2

[amr alanwar]

For printing an array normally, you can

fprintf('\n A1 =  ')
fprintf(' %.3f ',  A1)
fprintf('\n A2 =  ')
fprintf(' %.3f ',  A2)
fprintf('\n A3 =  ')
fprintf(' %.3f ',  A3)

The results

   A1 =   1.000  14.000  20.000  8.000 
   A2 =   5.000  1.000  20.000 
   A3 =   2.000

For your question, try playing with

    fprintf('%.0f.',  A1(1:end-1))
    fprintf('%.0f',  A1(end))

[James Tursa]

This does not give the desired outcome.

[amr alanwar]

I did not read the question carefully I modified my reply Thanks

Answer 3

[Captain Karnage]

Here's another alternative, more verbose but on a single line:

     A1 = [1 14 20 8];
     A2 = [5 1 20];
     A3 = [2];
          
     mystr = @(A) sprintf( [ repmat( '%d.', 1, numel(A) - 1  ), '%d' ], A );
     
     mystr(A1)

ans = '1.14.20.8'

     mystr(A2)

ans = '5.1.20'

     mystr(A3) 

ans = '2'