MATLAB: Extract number from file name

doublenumbernumericstring

There are several files like this: K10_0.0.json, Mig_Thresh_2.0.json, K_5_6.5.json, WC_0.00051.json, … and I need to extract the number after the last underline which would be 0.0 for K10_0.0.json, 2.0 for Mig_Thresh_2.0.json, 6.5 for K_5_6.5.json and 0.00051 for WC_0.00051.json. In other words, I need to get the number after the last underline (_).

Any idea how to do that?

Best Answer

Look at regexp function. I assume your input is a string array and you want a string array output.

a='K_5_6.5.json';
b=regexp(a,'(?<=[_])\d*[.]?\d*','match');
c=cell2mat(b(end));%c='6.5'

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A = {'jdldi'; 'jdks5.4555h'; 'f67'}
b=regexp(A,'\d+(\.)?(\d+)?','match')
out=str2double([b{:}])

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numstrs = regexp(TheString, '-?\d+(?=\s*s)', 'match');

and convert the resulting cells strings in to numeric forms.

The (?=\s*s) part is regexp-ese for "the expression after the '=' until the ')' must be matched in the input right after whatever was matched before this, but do not return this part as part of the match". Another way of phrasing this is that it "looks ahead" for the pattern but does not include it as part of what is matched.

\s*s stands for "any number of whitespace characters (including none), followed by the letter 's')

Best Answer

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MATLAB: Extract numbers from cell array

MATLAB: Edit user input

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