MATLAB: Finding a string with parentheses using regexp

find

A={'5123(P)';'5123 ESP'} how can i search A to find the cell that has the '(P)' string?
find(~cellfun(@isempty,regexp(A,'(P)'))); 
is giving 1 & 2 as answer which is not correct since it should be 1 only

Best Answer

 find(~cellfun(@isempty,regexp(A,'\(P\)')));
Explanation: parentheses are special characters in regular expressions, and need to be escaped to be treated as literal parentheses. Of course the documentation is the best place to learn how to to use regular expressions properly:
http://www.mathworks.com/help/matlab/matlab_prog/regular-expressions.html
Alternatively you could simply use strfind instead of regexp:
 find(~cellfun(@isempty,strfind(A,'(P)')))
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