How to count repeated rows of characters using a loop?

Say I have an array (I have already sorted alphabetically): results=[ABC;ABC;DEF;GHI;GHI;....]. I must use either a 'for' or 'while' loop (and I believe an 'if' statement will also make this easier) to find out how many times any repeated rows appear. i.e my above results would end up as [2;1;2;...]

thank you

[dpb]

For homework help, show your work to date and where you're specifically stuck...

[Jan]

"results=[ABC;ABC;DEF;GHI;GHI;...." is no valid Matlab syntax. Is this a cell string or a CHAR matrix? Some quote characters are missing in both cases.

[Jason]

I am GIVEN a CHAR matrix, all values already entered. To date all I have done is use "sortrows" to put the matrix in alphabetic order. My issue is coming to the loop, I have:

for 1:1:length(results)

if results(i,:)==results(i+1,:)

count= i+1

end

end

then matlab tells me "Index exceeds matrix dimensions"

Answer 1

[Image Analyst]

Hint: have you looked into sortrows() and unique()? If I were to do it for you, that's what I'd be looking up. Or maybe use hist(). Have you tried anything yet? Is this homework?

[Jason]

I've done sortrows() and tried playing around with unique(), but not hist(). I was able to make it work with:

[resultsx,resultsy]=unique(results,'rows');

n=accumarray(resultsy,1);

count = diff(resultsy)

But unfortunately I cannot use this since it is homework and we are specifically told to use a loop.

[Image Analyst]

Jason, you should have tagged it as homework. Please do so now. OK, so you have a loop over rows - that should be obvious, right. Now what? How about having another loop inside over rows from 1 to the current row where you check the current row against all 3 column elements of all prior rows ? That seems to make sense. Now if a match is found, you'll need to increment something, and if no match is found, it's the first one found so far so you need to set the count array to 1 for that pattern. Just think it through and you'll get it. Come back with more code if you have trouble. We can't just hand over to you a turnkey solution.