Keeping Previous Iteration changes

I am trying to change the user inputted text with the apropriate index of cipher vector. However, i cant seem to be able to keep the changes from the previous iterations of the for loop. How can i keep the changes with each iteration?

cipherVector = ['D','R','I','U','S','Y','A','Q','B','W','T','E','Z','N','L','P','M','O','C','V','H','G','F','J','X','K'];
letterVector = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'];
userEncrypt = input('Enter sentence','s')
for i= 1: strlength(userEncrypt)
    if ismember(lower(userEncrypt(i)), letterVector)
        x = strrep(userEncrypt, userEncrypt(i), cipherVector(strfind(letterVector,lower(userEncrypt(i)))))
    end
end

[Fabio Freschi]

Why did you delete your question? It could be of interest for Matlab community

[Adam Danz]

@Nelson Gonzalez, please revert your question. It's disrespectful to remove your question and make it useless after volunteers gave up their time to help you.

@Fabio Freschi, if you approximately remember the question I'd be glad to edit the question and replace the text if you don't have those privileges yet.

[Rena Berman]

(Answers Dev) Restored edit

[Adam Danz]

Thank you Rena Berman

Answer 1

[Fabio Freschi]

I see two problems in your code

1) the changes are only temporarily saved in x and x is never used

2) onec you change a letter, all the characters with that letter are changed, than the cypherLetter is changed again. For example if your sentence is 'aaa', after the first iteration you get 'DDD' and the second D is then processed at the second iteration.

I changed your code like this

cipherVector = ['D','R','I','U','S','Y','A','Q','B','W','T','E','Z','N','L','P','M','O','C','V','H','G','F','J','X','K'];
letterVector = ['a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z'];
userEncrypt = input('Enter sentence: ','s');

for i= 1: strlength(userEncrypt)
    % find position
    iPos = find(letterVector==lower(userEncrypt(i)));
    if ~isempty(iPos)
        userEncrypt(i) = cipherVector(iPos);
    end
end

disp(userEncrypt)

I hope this meets your initial request