MATLAB: Regular expressions resources and regular expression problem

parserregular expressionsstring

Hi all, I don't know anything about regular expressions and I have two questions:
  1. What is the most effective way to learn regular expressions and where to find the best possible tutorials, examples, exercises etc.
  2. I have the following problem. I would like to extract (1) a list variables and (2) a list of matlab functions from a string. The variables have a precise definition: (i) they can start with 'a' 'd' or 'ee'; (2) then an underscore '_'; (3) then an integer 'n'. For example, the variables could be 'a_1', 'd_100', 'ee_3289' and the expression to parse could look like: 'cos(exp(a_2/4*d_1^3-ee_4)+d_85)'. In this example, the list of variables is 'a_2', 'd_1', 'ee_4', 'd_85' and the list of matlab functions is 'cos', 'exp'. My question here is what is the (best) regular expression to extract that information?
Thanks, Pat

Best Answer

1. Read here about the Regular Expressions
2.
str = 'cos(exp(a_2/4*d_1^3-ee_4)+d_85)';
fun = regexp(str,'\w*(?=\()','match')
var = regexp(str,'(a|d|ee)_\d*','match')
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