Finding common strings elements in array?

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Ryan 2013-9-30

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https://ww2.mathworks.cn/matlabcentral/answers/88715-finding-common-strings-elements-in-array

评论： Ryan 2013-10-2

Hi,

So this seems ridiculously easy but for some reason I can't find a solution. I imported an excel file into matlab and wanted to extract data after a specific date. The problem is that the elements are at the end in each date and not beginning.

I want to have an index of cells that have a common given year. They are formatted this way in each cell: '5/22/2000'

strmatch from my understanding finds common elements but mine are at the end....

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Image Analyst 2013-9-30

Can you attach the workbook, or at least enough of it so we can try to read it in?

Ryan 2013-10-2

Yes I will try to get that to you later today. Thanks!

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Answer 1

Jan 2013-9-30

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Do you want to search for the final part of a string? Then http://www.mathworks.com/matlabcentral/fileexchange/27032-strncmpr would help:

C = {'5/22/2000', '5/22/2001', '15/23/2000'};
index = find(strncmpr(C, '2000', 4));
% >> index = [1, 3]

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Ryan 2013-10-1

Thanks for the response. When I run your function it says "Cannot find compiled Mex file".

Jan 2013-10-2

Then please read the instructions provided inside the file, especially the point "COMPILATION". There you find a link to download pre-compiled MEX files also.

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Answer 2

Jos (10584) 2013-10-2

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编辑：Jos (10584) 2013-10-2

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Get the final part of the strings, and compare them:

C = {'5/22/2000', '5/22/2001', '15/23/2000'} % example from jan
tf = strcmp(cellfun(@(x) x(end-3:end),C,'un',0),'2000')

Another, easier approach:

[y,m,d] = datevec(C,'mm/dd/yyyy')
tf = y == 2000

but note that for this to work the dates should be valid. C{3} is NOT a valid date ( was that intentionally, Jan? ) so that is why tf(3) is false ...

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Ryan 2013-10-2

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Thanks for this Jos however I don't think the latter option is working. I imported an excel document that has a list of rows that are like below and it is giving me the error:

"[y, m, d] = datevec(txt(1:3,1),'mm/dd/yyyy'); Error using dtstr2dtvecmx Failed on converting date string to date number. Error in datevec (line 118) y = dtstr2dtvecmx(t,icu_dtformat);"

The array is like this: