MATLAB: Regular Expression pattern for matching a variable name after an operator (mathematical or logical)

regexpregexprepregular expressions

Hello, i am new to regular expressions and using regexprep as well. I want to write a function which replaces names of variables with a given new name. The expression i used first was (^|\W)oldName(\W|$) and $1newName$2 as the replacement.
Unfourtunatly this will not replace expressions like variableA*variableA or variableB+variableB. The second factor or summand is not replaced so i have to do regexp() twice. Secondly i tried the expression (^*|\W)oldName(\W|$) which will replace the second factor in the example above, but will also replace the name in something like this: thisvariableA.
matchPattern = (^|\W)oldName(\W|$);
replacePattern = $1newName$2;
StringContent = 'oldName*oldName';
ContentNew = regexprep(StringContent , replacePattern , matchPattern);
So i am looking for a regexp pattern which matches 'oldName' also after an operator which follows after and before'oldName'. A way to match the given example would help.

Best Answer

>> regexprep('variableA*variableA','(?<=\W)\w+','newName')
ans = variableA*newName
>> regexprep('variableB+variableB','(?<=\W)\w+','newName')
ans = variableB+newName
Your specification is quite vague: do you want to replace all of the instances of variableX with newName, or only the one after the operator (as your title states)? To learn how to write regular expressions read this page very carefully, and refer to it all the time:
https://www.mathworks.com/help/matlab/matlab_prog/regular-expressions.html
You might also be interested in downloading my FEX submission iregexp, which provides an interactive tool for experimenting with regular expressions and showing regexp's outputs as you type:
https://www.mathworks.com/matlabcentral/fileexchange/48930-interactive-regular-expression-tool
It is useful for quickly experimenting with and refining regular expressions.
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