Python中的正则表达式模式可在文件内搜索文本块

Question

Hello I am new to regex and I am trying to compile a regex to match the text block below, there are multiple such text blocks in a file and I would like to move these blocks to another file. Kindly help me!

conversion DC_PRESS_1024 {
    kind = conversionKind rationalFunction;
    physMin = 0;
    physMax = 10;
    coefficients = ( 
        0;
        1024;
        0;
        0;
        0;
        1;
    )
    comments = 
        commentVal {
            value = 
                mlString {
                    value = "[VIT_DDS]External_CompuMethod";
                    language = language en;
                }
            kind = commentKind internal;
        }
}

Note: The contents inside conversion XX_XXXX_XXX{ } vary. I want to search for the entire block irrespective of the name ie XX_XXXX_XXX and the content inside {}.

Answer 1

The difficult bit here is to manage opening and closing curly brackets. If you have potentially unlimited depth for nesting the brackets, then I don't think you can do it with regular expressions, because it would be a recursive pattern. In that case you would need a parser , keeping track of the opened brackets and reading the text token by token.

But if you know already that it is impossible to have more than two levels of nesting inside blocks (like in your example), then you can use a regular expression like this one:

conversion\s*\w+\s*\{([\s\w\;\=\(\)\[\]\"]|(\{([\s\w\;\=\(\)\[\]\"]|(\{[\s\w\;\=\(\)\[\]\"]+\}))+\}))+\}

See it in action at: http://regexr.com/3b794