Matching occurrence in string with regex for value replacement?

Question

I've spent some time on this problem but really need help from a regex guru.

So far I have the following which doesn't quite give me what I need.

[.*?]\s[=><]+\s[@]\w+

From the following sample string, I need all occurrences of a field followed by a parameter\variable. A parameter starts with an '@'.

I am then going to use the result to replace the contents of each value in .net.

Therefore, the regex expression would match

[System.TeamProject] = @project
[Microsoft.VSTS.Common.ClosedDate] >= @startOfDay
[Microsoft.VSTS.Common.ClosedDate] >= @startOfDay

Note [System.State] = 'Closed' is not matched.

Sample string

select [System.Id], [System.WorkItemType], [System.Title], [System.AssignedTo], [System.State], [System.Tags] from WorkItems where [System.TeamProject] = @project and [Microsoft.VSTS.Common.ClosedDate] >= @startOfDay and [System.State] = 'Closed' and [Microsoft.VSTS.Common.ClosedDate] >= @startOfDay

Thanks heaps!

Answer 1

This regex should do what you want:

\[([^]]*)]\s+[><=]+\s+(\@\w+)

The main change is that the [ and ] in the initial part of your regex needed to be escaped. I have also added capture groups to collect the field name (group 1) and parameter value (group 2).

Demo on regex101

Answer 2

My guess is that maybe you're trying to write some similar expression to:

\[([^\]]*)\]\s*(=|>=|<=)\s*(@\w+)

and replace with some string similar to:

[new_value] $2 $3

I've added some capturing groups, wasn't sure about the desired output, you can simply remove or modify those if/as you wish.

Demo

Test

using System;
using System.Text.RegularExpressions;

public class Example
{
    public static void Main()
    {
        string pattern = @"\[([^\]]*)\]\s*(=|>=|<=)\s*(@\w+)";
        string substitution = @"[new_value] $2 $3";
        string input = @"select [System.Id], [System.WorkItemType], [System.Title], [System.AssignedTo], [System.State], [System.Tags] from WorkItems where [System.TeamProject] = @project and [Microsoft.VSTS.Common.ClosedDate] >= @startOfDay and [System.State] = 'Closed' and [Microsoft.VSTS.Common.ClosedDate] >= @startOfDay

Note [System.State] = 'Closed' is not matched.";
        RegexOptions options = RegexOptions.Multiline;

        Regex regex = new Regex(pattern, options);
        string result = regex.Replace(input, substitution);
    }
}

---

If you wish to simplify/modify/explore the expression, it's been explained on the top right panel of regex101.com . If you'd like, you can also watch in this link , how it would match against some sample inputs.

---

RegEx Circuit

jex.im visualizes regular expressions: