Creating a Wordscramble using matlab

Hi, working on a review sheet (not for a grade), and I need to create a function that recieves a word and scrambles every letter except for the first and last letters of the word. I've already created a function that scrambles a word entirely in a previous problem, but I can't figure out how to rearrange it to leave the first and last letters unscrambled. Here's my function:

function outword =wordscramble(inword)
len = length(inword);
% Puts random index in the first element
indvec = zeros(1,len);
indvec(1) = randi([1 len]);
% Makes sure every index is only used one time
for i = 2:len
  ran = randi([1 len]);
  while any(indvec(1:i-1)== ran)
     ran = randi([1,len]);
  end
  indvec(i) = ran;
end
outword = inword(indvec);
end

Answer 1

[Ameer Hamza]

Try this

function outword = wordscramble(inword)
    outword = inword;
    n = numel(inword);
    idx = randperm(n-2)+1;
    outword(2:end-1) = outword(idx);
end

Example

>> wordscramble('A quick brown fox')
ans =
    'Acqoouwb f r iknx'

[AJ Schmidt]

Although your function yields the correct answer, my instructor hasn't taught us the randperm function yet, so I wouldn't be able to use that function on a test or homework assignment. Thanks for finding an answer!

[Ameer Hamza]

Try this version free of randperm:

function outword = wordscramble(inword)
    outword = inword;
    n = numel(inword);
    vec = 2:n-1;
    idx = zeros(size(vec));
    for i=1:numel(vec)
        I = randi([1 numel(vec)], 1);
        idx(i) = vec(I);
        vec(I) = [];
    end
    outword(2:end-1) = outword(idx);
end

Test:

>> wordscramble('A quick brown fox')
ans =
    'Ao  oi bfcnurkwqx'

[AJ Schmidt]

That should do the trick, thanks for your help!

[Ameer Hamza]

I am glad to be of help.

[Stephen23]

You can create your own randperm by sorting any random vector of numbers:

>> str = 'A quick brown fox';
>> [~,idx] = sort(rand(1,numel(str)));
>> str(idx)
ans = uoqbio kAfwcx  rn