Question

I am trying to parse some C# code to Python. There are several regular expression in that code. Everything worked fine so far, but now I’ve got the following problem:

C# Code:

Match m = regEx.Match( Expression );
while( m.Success )
{
    Expression = Expression.Replace( m.Value, m.Groups[1].Value + this.Solve( m.Groups[2].Value ) );
}

What can I do to make this code working in python? I’ve already tried something like this:

matchObj = re.search(pattern = p, string = expression, flags = re.IGNORECASE)
while matchObj:
    if len(matchObj.group(3)) > 0:
        expression = re.sub(pattern = p, repl = matchObj.group(1) + self.solve(matchObj.group(2)), string = matchObj.string, flags = re.IGNORECASE) #Here is the problem...

So actually I am looking for something equivalent of matchObject.Value.

Thank you for your help.

Answer 1

I think this is what you are trying to do; match.group() (without a parameter) returns the match the whole regex matches:

m = re.search( pattern, text )
if m and len( m.group(3) ) > 3:
    text = text.replace( m.group(), m.group(1) + solve( m.group(2) ) )

I’m not sure why you had a loop there, so I removed it. Another way, without using str.replace would be to manipulate the string based on the positions returned by m.start() and m.end().