How to replace surrounding groups of a match using regex?

Question

I have the following string:

[Element][TOPINCLUDESAMEVALUES:5][ParentElement][ORDERBY:DateAdded]

and want to transform it to this:

[Element][TOP:5:WITHTIES][ParentElement][ORDERBY:DateAdded]

So, the [TOPINCLUDESAMEVALUES:5] is transform to [TOP:5:WITHTIES].

The input string could contain more [elements]. Each element is surrounded by square brackets []. For example:

...[element1][element2][TOPINCLUDESAMEVALUES:5]...[element3][element4][TOPINCLUDESAMEVALUES:105][element3]...

So, I need to transform each [TOPINCLUDESAMEVALUES:X] element to [TOP:X:WITHTIES] elements.

Generally, I try some combinations using regex replace substitutions but was not able to do it myself.

 string statement = "[Campaign][TOPINCLUDESAMEVALUES:5][InstanceID][GROUPBY:Campaign]";
 statement = Regex.Replace(statement, @"(?<=\[TOPINCLUDESAMEVALUES:)[^\]]+(?=\])", "");

Could anyone tell is there a way to do such replace?

Not knowing the load of data you'd be evaluating for replacement, but you might want to consider a manual replacement algorithm over regex for performance. — Shar1er80
– Shar1er80, Commented Jul 30, 2015 at 14:35

Sergey Kalinichenko · Accepted Answer · 2015-07-30 13:51:08Z

2

Since you are replacing the content of TOPINCLUDESAMEVALUES with something else, you need to capture it. Lookbehind that you are using is non-capturing, so you wouldn't be able to replace its content.

Here is how you should be able to do it:

statement = Regex.Replace(
    statement
,   @"\[TOPINCLUDESAMEVALUES:([^\]]+)\]", "[TOP:$1:WITHTIES]"
);

This expression would match the entire [TOPINCLUDESAMEVALUES:5] bracketed portion, and additionally capture 5 as capturing group number 1. The replacement value refers to that group as $1, pasting its content in between TOP: and :WITHTIES.

Demo.

answered Jul 30, 2015 at 13:51

Sergey Kalinichenko

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Comments

Amit Tiwari · Accepted Answer · 2015-07-30 14:09:39Z

0

try this

    string statement = "[Campaign][TOPINCLUDESAMEVALUES:5][InstanceID][GROUPBY:Campaign]";
    string[] arrstatement = "[Campaign][TOPINCLUDESAMEVALUES:5][InstanceID][GROUPBY:Campaign]".Split(']');
    for (int i = 0; i < arrstatement.Length; i++)
    {
        if (arrstatement[i].Contains("TOPINCLUDESAMEVALUES"))
            arrstatement[i] = "[TOP" + arrstatement[i].Substring(arrstatement[i].IndexOf(":")) + ":WITHTIES";
    }
    statement = string.Join("]", arrstatement);

answered Jul 30, 2015 at 14:09

Amit Tiwari

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