FUNCTION::NGROUPS(3stap)

💖 FUNCTION::NGROUPS 💖

okay bestie, we're in the 3stap manual — the SystemTap Tapset Reference situation — and this little cutie is a function, so let's get into it 🫶

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✨ NAME ✨

function::ngroups — Number of subexpressions in the last match. literally that's the whole job. she's niche but she's iconic 👑

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🌸 SYNOPSIS 🌸

ngroups:long()

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🎀 ARGUMENTS 🎀

None. no arguments, no notes, she takes nothing from you 💅

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🦋 DESCRIPTION 🦋

So ngroups returns the number of subexpressions from the last successful use of the =~ regex matching operator. that's it. that's the vibe check ✨

Now here's the part you gotta hear, no cap: this number includes subexpressions that are present in the regex but did not match any string. so if you're like "wait, that group didn't match anything, why is she counted" — because that's just how it is, bestie 😭 for example, given the regex "a|(b)", the subexpressions will count the group for (b) regardless of whether it matched a string or not. counted anyway. she said inclusivity periodt 💜

⚠️ and be careful: it throws an error if the last use of =~ was a failed match. so like... if the match flopped, don't come asking her for a number, she will simply scream at you. main character energy but make it hostile 🙈

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🌈 SEE ALSO 🌈

• tapset::regex(3stap)

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and that's the whole page, you ate it 💅 this was the SystemTap Tapset Reference, version note dated September 2026 — mwah, go slay some regexes, ily 🧚💖✨