How to count repeated rows of characters using a loop?

2 次查看（过去 30 天）
Jason
Jason 2014-3-23
评论： Image Analyst 2014-3-23
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
  3 个评论
显示 1更早的评论
Jan
Jan 2014-3-23
"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
Jason 2014-3-23
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"

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Image Analyst
Image Analyst 2014-3-23
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?
  2 个评论
Jason
Jason 2014-3-23
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
Image Analyst 2014-3-23
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.

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Matrix Indexing 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by