Regex with Qt capture some text

Question

I would like to capture second occurence of the text replaced by a star in the following string:

&nbsp;SW * <br>

ie string starting with  SW ending with <br> in a QString, using the RegEx with Qt.

an example here: the string is

&nbsp;&nbsp;SW = min(1, max(0, pow(10, -0.2 - 6.5 ) ** (1.0 / 0.2)))<br>

and expected result is

= min(1, max(0, pow(10, -0.2 - 6.5 ) ** (1.0 / 0.2)))

So far, i have QRegExp rx("^[\ SW](.*)[<br>]$"); which is not compiling.

How would you do ?

I'd start with a tutorial about Regular expressions. Look at some examples and how you have to write syntax. Then, try some example lines with an online regexp tester, and start working from there. — MatthiasB, Mar 06 '14 at 11:06

score 1 · Accepted Answer · answered Mar 06 '14 at 11:11

The compilation issue is probably due to trying to escape the ampersand (\&). But other than that, your regex is mostly right, just overusing character groups ([]), they are not for grouping. This expression works in my tests:  SW(.*)<br>, so in your case you'd do something like

QRegExp rx("&nbsp;SW(.*)<br>")

score 0 · Answer 2 · answered Mar 06 '14 at 13:26

the exact pattern was QLatin1String(".* SW([^<]*)<br>.*") and for capture this code was working for me

       QRegExp rx(QLatin1String(".*&nbsp;SW([^<]*)<br>.*"));

       int p = 0;
       QString cap ;
       if((p = rx.indexIn(str, p)) != -1) 
           cap = rx.cap(1).trimmed();

nota bene: should capture first occurrence for element within the parenthesis with cap(1) and not cap(0) which capture of the whole pattern and not the content of the parenthesis.

Regex with Qt capture some text

2 Answers2