How to find the position of a specific characters containing in a string in a cell array

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Jo 2014-10-22

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评论： Guillaume 2014-10-22

采纳的回答： Guillaume

hello. i have a 136x39 cell array like this one

'Data Name' 'Timestamp' 360 370

'001-Day 1-RE-1' '24/07/2014 10:17:10' -738.803345332164 -734.184486898226

'001-Day 1-RW-1' '24/07/2014 10:17:37' -707.272295650121 -703.634423319119

'001-Day 1-LE-1' '24/07/2014 10:19:20' -744.635983922777 -740.346463517543

'001-Day 1-LW-1' '24/07/2014 10:19:39' -751.552763303339 -747.041101104821

and I want to find the positions of 'RE','RW','LE','LW'. I tried with the function [RW1, RW2]=find(strcmp('RW', array)); but got no results. I also tried [RW1, RW2]=find(strcmp('*RW*', Acdelta)); or strfind..

Any ideas?

Many thanks

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Answer 1

Guillaume 2014-10-22

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Use either strfind four times, once for each pattern (RE, RW, LE, LW). Note that strfind (and strcmp) does not accept wildcards, or regexp

pos = regexp(array(:, 1), 'RE|RW|LE|LW', 'once');

Note that you can't pass the full cell array to strfind or regexp, since it contains elements that are not strings. Here, I just pass the first column.

Also, in your example, the position is always the same, so why do you want to find it?

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Jo 2014-10-22

yes you are right. 'RE', 'RW' is the 10th character in this array but it may change in a different one, that's why I am looking for 'RE', 'RW' only. Each of 'RE', 'RW', appears to have 4 different values for each day (day1, day2,..). So I want to find the positions (values) and calculate the mean for each day. In a different array, where 'LW' wasn't part of a string, I used the function [LW1, LW2]=find(strcmp('LW', array)), found the positions of LW and calculated the mean as I described above.

Guillaume 2014-10-22

在 MATLAB Online 中打开

Ok, I'm still not very clear on what you're trying to do and whether or not your question is actually answered.

If you want the position and the value that follows the 'RE/RW/LE/LW', you can use a different regular expression:

[pos, valuestr] = regexp(array(:, 1), '(?:RE|RW|LE|LW)-(\d+)', 'start', 'tokens', 'once');
values = cellfun(@(v) str2double(v), valuestr, 'UniformOutput', false);