use function unique and find in two different sheets of xls

My data is more than one sheets of excel(the number of rows are more than one sheet), but I need to find the unique value in one column.is it possible to write code in way that function unique works in way that thinks two sheets are continues each other?

Answer 1

[dpb]

Not directly, no.

Read both sheets; concatenate the two and call unique on the result, or

Read first sheet, call unique on that portion; rinse repeat for second then return intersection of the two results.

[Nooshin Mahmoodi]

thanks for your reply, I think it is not possible to concatenate them(my data is more than one sheet), is there anyway?? I will try the second way. thanks a lot.

[dpb]

Of course it's possible (presuming sufficient memory)...

x=xlsread(file,sheet1);
x=[x;xlsread(file,sheet2);];

if the data in the two sheets are commensurate in horizontal shape so can paste the two arrays together.

[madhan ravi]

+1 @dpb clarified my doubt too thank you!

[dpb]

NB: For such large datasets, Excel and xlsread/write are notoriously slow; using a "stream" file externally and then .mat file for ML data would be much faster.

[Nooshin Mahmoodi]

my data are the same in the vertically (columns). sorry, but what is the stream? I never use it

[dpb]

Simply the "stream" of bytes written/read to/from disk w/o the overhead of character translation/formatting. Often called "binary". Use fopen/close, fread/write and friends in Matlab.

Where are all these data coming from and how are they getting into Excel? There would be the place to start removing bottlenecks and making savings/increasing efficiency.