How can I plus (append) string in each loop?

I have:

person=[1,2];
for i=1:length(person) 
  if (person(i))== 1
    str=sprintf('Person A');
  elseif (output(i))==2
    str=sprintf('Person B');
  elseif (output(i))==3
    str=sprintf('Person C');
  elseif (output(i))==4
    str=sprintf(' Person D');
  elseif (output(i))==5
    str=sprintf('Person E');
  else
    str=sprintf('System can not detect!');            
  end
end

 %How can I plus result in each loop, like this: 
%str='Person A Person B' 
How can I plus result in each loop, like this: 
str='Person A Person B' 
Thank for your help!

Answer 1

[Image Analyst]

Here's another one of many ways. Not necessarily the best, but along the lines of what you started with. (Is this homework?)

person=[1, 2];
finalString = ''; % Initialize
for i=1:length(person)
  if (person(i))== 1
    str=sprintf('Person A');
  elseif (person(i))==2
    str=sprintf('Person B');
  elseif (person(i))==3
    str=sprintf('Person C');
  elseif (person(i))==4
    str=sprintf('Person D');
  elseif (person(i))==5
    str=sprintf('Person E');
  else
    str=sprintf('System can not detect!');
  end
  finalString = [finalString, ' ', str]; % Append this string.
end
fprintf('The final string = %s\n', finalString);

[Yen Hai]

Thanks "Image Analyst"! Yes, it's my homework. I am studying about image processing, I have just begun with matlab programming. Hopefully I can get some help from you!

[Image Analyst]

Sure, just ask, but remember to attach your images and explain the larger context of what you want.

Answer 2

[dpb]

I presume output is a typo intending person. But you don't need a loop nor any logical tests at all...

>> people=['A':'Z'];  % define population of names from which to pick
>> persons=1:3:8;     % chose some arbitrarily
>> sprintf('Person %2c ',people(person))
ans =
Person  A Person  D Person  G 
>>

BTW, if don't want the trailing blank or it's a bother, simply wrap with

strtrim(sprintf('Person %2c ',people(person)))

[Yen Hai]

Thanks "dpb"!