> On 10 Aug 2020, at 18:36, Bert Gunter <bgunter.4...@gmail.com> wrote: > > But this appears to be imprecise (it confused me, anyway). The usual sense > of "matching" in regex's is "match the pattern somewhere in the string > going forward." But in the perl lookahead construct it apparently must > **exactly** match *everything* in the string that follows. > > Questions: > Am I correct about this? If not, what do I misunderstand?
I think you're confused about the terminology. To _match_ a regular expression is to find a substring described by the regexp at a given starting point; what you have in mind is to _search_ a string for matches of a regular expression. Python uses this terminology in its regexp matching functions, and from what you cited in the documentation so do Perl and PCRE in their docs. Best, Stefan ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
