MATLAB: String and character array not properly printing

fprintfinputstringstrvcat

I am trying to write a prompt for input from the user in a subfunction. This prompt will be dependent upon the name of the files they have loaded in another subfunction. I can get Matlab to correctly write the string (as shown when I look at the variable while debugging) using the following code,
 function GraphIt (filenamestr)
  promptopt=strings(1,length(filenamestr));  %preallocating
  prompt=sprintf('Which file do you want to graph from? (Please input number)'); %first line of prompt
  for i=1:length(filenamestr) %Writing string 
   promptopt=sprintf(' %d. %s',i,filenamestr(i));
   prompt=strvcat(prompt,promptopt);
  end
funcstr=input(prompt); %User input
However I cannot get the string to properly print via fprintf or the prompt of the input. I have tried using the char command (with \n at the end of each line) instead of strvcat to write the text as a character array but I still have the same problem.
Please note that the string has characters such as ()-, in it.
For reference the string prints as:
 W  h12i..c  h0L .if1Bi NlMMe B B dLmoDi -cyIro-ou1e 2lw0ea cnpttor lotydo(e L gi6rBVaN pMchBy )cf lr(io1nm.g?5.  t(mxPLtl) e  am si en  i i  nb pa ut th    nt ue ms bt e, r  )i  n  s  i  d  e     g  l  o  v  e  b  o  x  ,     t  e  f  l  o  n     c  a  p  ,     P  t     m  i  c  r  o  e  l  e  c  t  r  o  d  e  ,     6     V     5  0     c  y  c  l  e  s  ,     0  .  0  1  V  s  .  t  x  t W  h12i..c  h0L .if1Bi NlMMe B B dLmoDi -cyIro-ou1e 2lw0ea cnpttor lotydo(e L gi6rBVaN pMchBy )cf lr(io1nm.g?5.  t(mxPLtl) e  am si en  i i  nb pa ut th    nt ue ms bt e, r  )i  n  s  i  d  e     g  l  o  v  e  b  o  x  ,     t  e  f  l  o  n     c  a  p  ,     P  t     m  i  c  r  o  e  l  e  c  t  r  o  d  e  ,     6     V     5  0     c  y  c  l  e  s  ,     0  .  0  1  V  s  .  t  x  t
when it should be:
 Which file do you want to graph from? (Please input number)
  1. 0.1 M BLD-I-120 poly(LiBNMB) (1.5 mL) mini bath test, inside glovebox, teflon cap, Pt microelectrode, 6 V 50 cycles, 0.01Vs.txt
  2. LiBNMB microelectrode 6V cycling.txt
Thanks for your help!

Best Answer

Two things happen here: input actually only accepts a character vector for prompt but you are providing it with a matrix, and you then failed to take into account the fact that MATLAB is column-major (so that when you provide a non-supported matrix prompt to input then MATLAB converts this into one row character vector using the column-major sequence). Your characters are certainly all there, you can clearly see how they have been arranged:
         W  h12i..c  h0L .if1Bi NlMMe B B dLmoDi -cyIro-ou1e 2lw0ea cnpttor lotydo(e ...
  row 1: W  h  i  c  h     f  i  l  e     d  o     y  o  u     w  a  n  t     t  o   ...
  row 2:     1  .     0  .  1     M     B  L  D  -  I  -  1  2  0     p  o  l  y  (  ...
  row 3:      2  .     L  i  B  N  M  B     m  i  c  r  o  e  l  e  c  t  r  o  d  e ...
The solution is to not use strvcat, but concatenate the substrings properly into a single vector, so that you can provide a character vector just as the input help requests. You should always use the 's' option too, to avoid magically evaluating whatever input the user gives. Here is one solution (untested):
function GraphIt(filenamestr)
prompt = 'Which file do you want to graph from? (Please input number)');
for k = 1:numel(filenamestr)
   prompt = sprintf('%s\n %d. %s', prompt, k, filenamestr(k));
end
funcstr = input(prompt,'s');
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