'\" t
.\"     Title: function::ngroups
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: November 2023
.\"    Manual: A collection of standard string functions
.\"    Source: SystemTap Tapset Reference
.\"  Language: English
.\"
.TH "FUNCTION::NGROUPS" "3stap" "November 2023" "SystemTap Tapset Reference" "A collection of standard strin"
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.SH "NAME"
function::ngroups \- Number of subexpressions in the last match\&.
.SH "SYNOPSIS"
.sp
.nf
    ngroups:long()
.fi
.SH "ARGUMENTS"
.PP
None
.SH "DESCRIPTION"
.PP
returns the number of subexpressions from the last successful use of the =~ regex matching operator\&.
.PP
Note that this number includes subexpressions which are present in the regex but did not match any string; for example, given the regex
\(lqa|(b)\(rq, the subexpressions will count the group for (b) regardless of whether it matched a string or not\&. Throws an error if the last use of =~ was a failed match\&.
.SH SEE ALSO\n 
.IR tapset::regex (3stap)