Strange results from unique

Question

David Winthrop 2021-5-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/841765-strange-results-from-unique

编辑： David Winthrop 2021-5-27

采纳的回答： Walter Roberson

I recently encountered a strange result that defies explanation. I took a screenshot. How can this be?

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

the cyclist 2021-5-27

It's always better to upload the data and code, rather than an image (which we cannot work with).

Yes, someone might be able to eyeball what is going on, but usually not.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2021-5-27

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/841765-strange-results-from-unique#answer_710965

在 MATLAB Online 中打开

XLv{1} is a vector of 702 elements, YLv{1} is a vector of 702 elements. When you combine them you get 702 unique rows. But that does not imply that there are no duplicates amongst Xlv{1] or YLv{1} .

4 unique rows, right?

Now let XLvs be [1 2] and YLvs be [3 4]. ismember([1 1 2 2], [1 2]) would be [true true true true], ismember([3 4 3 4], [3 4]) would be [true true true true]. & the two of them to get [true true true true], which has a sum of 4... even though there are only 2 unique values in each of XLvs and YLvs.