C# Regex Select predefined keywords with bracket

Question

I have a text which is

SMA(20, V1) > 200000 AND C1 < LowerBollingerBand(20, 2)

after applying regex I need a result like this

SMA(20, V1) LowerBollingerBand(20, 2)

I can select SMA and LowerBollingerBand by defining these keywords explicitly like this

(SMA|LowerBollingerBand)(\()

But I am unable to select whatever comes between brackets followed by brackets

Can the parentheses be nested? Are you looking for just `(SMA|LowerBollingerBand)\([^()]*\)`? — Wiktor Stribiżew, Oct 07 '16 at 11:26
not now but may be if any string becomes complex then there will nested parentheses — Haseeb Khan, Oct 07 '16 at 11:27
(SMA|LowerBollingerBand)\([^()]*\) its exactly what I wanted for now — Haseeb Khan, Oct 07 '16 at 11:29
Did I muss anything or will `(.*) > \d{6} AND C1 < (.*)` suffice? — MakePeaceGreatAgain, Oct 07 '16 at 11:33

score 1 · Accepted Answer · edited May 23 '17 at 10:27

In case your strings cannot have nested balanced parentheses, you may use a [^()] negated character class to match any symbol but ( and ) after \( and add a \) after to match the close parentheses:

(SMA|LowerBollingerBand)\([^()]*\)

See the regex demo

Details:

(SMA|LowerBollingerBand) - either SMA or LowerBollingerBand
\( - a (
[^()]* - 0+ chars other than ( and )
\) - a ).

In case there are balanced nested parentheses, use

(SMA|LowerBollingerBand)\((?>[^()]+|(?<c>)\(|(?<-c>)\))*(?(c)(?!))\)

See this regex demo

The \((?>[^()]+|(?<c>)\(|(?<-c>)\))*(?(c)(?!))\) construct matches balanced nested parentheses, see this answer for a description. More on this can be found at the regular-expressions.info Balancing Groups.

C# Regex Select predefined keywords with bracket

1 Answers1