Find a string in a text file and replace it by elements of a matrix

I have a text file str = 'C:\KR.txt'. somewhere in the file I have the following:

 -- this is what to change
  [$1]
  /

I want a code to find [$1] and replace it with element of an array A. For example suppose that A has 3 columns and 4 rows A= [1 2 3; 4 5 6; 7 8 9; 10 11 12]. So I should have this

 -- this is what to change
  1 2 3
  4 5 6
  7 8 9
  10 11 12
  /
I tried to use this
str = strrep(str, '[$1]',mat2str(A));

but the results are not as I expect. Can you please suggest ? Thank you

Answer 1

[Cedric]

Instead of mat2str(A), use the following

 Astr = sprintf( [repmat('%d ', 1, size(A, 2)), '\r\n'], A.' ) ;
 str  = strrep( str, '[$1]', Astr ) ;

Or, the more versatile (because you leave it to NUM2STR to use the correct format)

 Astr = sprintf( [num2str(A), repmat('\r\n', size(A, 1), 1)].' ) ;
 str  = strrep( str, '[$1]', Astr ) ;

Note that you might want to remove the \r if you are working in a UNIX-like environment.

[Cedric]

I may have edited my answer after you read it, because when I saved the edit you had already accepted the answer. Sorry for this.