MATLAB: Change digits in strings

regexprepstrings

Hello,

I have a problem. How I can change digits in string for example:

"A[12,12]*A[12,12]+A[9,12]*A[12,9]+A[5,2]*A[1,3]"

to have

"A[11,11]*A[11,11]+A[8,11]*A[11,8]+A[4,1]*A[0,]"

using regexprep ?

Best

You need to use a dynamic replacement string

str = '"A[12,12]*A[12,12]+A[9,12]*A[12,9]+A[5,2]*A[1,3]"';
regexprep(str, '\d+', '${num2str(str2double($0)-1)}')

Assuming that the '1.1.2' must be at the beginning of a line in a multiline string, this simple regular expression would work:

loc = regexp(yourstring, '^1\.1\.2[^.0-9]', 'lineanchors')

If the criteria is that '1.1.2' must not be preceded by a 'number dot' nor followed by a 'dot number' then:

loc = regexp(yourstring, '(?<!\d\.?)1\.1\.2[^.0-9]')

For #1 you could use isstrprop().

For #2, see startsWith(str, '_') and endsWith(str, '_')

For #3, you can use find():

indexes = strfind(str, '__');

For #4 you could do something like

if str(1) >= '0' && str(1) <= '9'
    % str starts with a numerical digit.
else
    % str does not start with a numerical digit.
end