Regex to return the first pattern match in a string

Question

For the given xml formatted string

<ItemGroup>
    <PackageReference Include="Bond.CSharp" />
  </ItemGroup>

<ItemGroup>
    <PackageReference Include="Bond.CSharp" />
  </ItemGroup>

I am attempting to capture

<ItemGroup>
    <PackageReference

using the following Regex:

<ItemGroup>\s*<PackageReference

How can I limit the result to just the first match and not get both ItemGroups?

I am using C# flavored regex

I tried using

 (<ItemGroup>\s*<PackageReference)+?

and

<ItemGroup>\s*<PackageReference{0,1}

but neither approach worked for me

blhsing · Accepted Answer · 2022-11-01 01:21:49Z

1

You can use .* with the Singleline flag to consume all characters after the first match of <ItemGroup>\s*<PackageReference so that there won't be a second occurrence. Capture the desired portion in parentheses as a group:

Regex regex = new Regex(@"(<ItemGroup>\s*<PackageReference).*", RegexOptions.Singleline);
MatchCollection matches = regex.Matches(xml);
foreach (Match match in matches) {
    GroupCollection groups = match.Groups;
    Console.WriteLine(groups[0].Value)
}

edited Nov 1, 2022 at 1:21

answered Nov 1, 2022 at 1:16

blhsing

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2 Comments

bob Over a year ago

Unfortunately, this doesn't work for me. Using SingleLine yields a single Match incl all PackageReference. Removing single line gives me 1 match but with Include= <ItemGroup> <PackageReference Include="Bond.CSharp" />

bob Over a year ago

It works by adding ? after the .* in your regex expression and removing singleLine. Thanks for your help.

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