Rau, Roland wrote:
>
> P.S. Any suggestions how to become more proficient with regular
> expressions? The O'Reilly book ("Mastering...")? Whenever I tried
> anything more complicated than basic usage (things like ^ $ * . ) in R,
> I was way faster to write a new function (like above) instead of finding
> a regex solution.
>
the book you mention is good.
you may also consider http://www.regular-expressions.info/
regexes are usually well explained with lots of examples in perl books.
> By the way: it might be still possible to *write* regular expressions,
> but what about code re-use? Are there people who can easily *read*
> complicated regular expressions?
>
in some cases it is possible to write regular expressions in a way that
facilitates reading them by a human. in perl, for example, you can use
so-called readable regexes:
/
(.+) # match and remember at least one arbitrary character
[.] # match a dot
[^.]+ # match at least one non-dot character
$ # end of string anchor
/x;
you can also use within regex comments:
/(.+)(?# one or more chars)[.](?# a dot)[^.]+(?# one or more
non-dots)$(?# end of string)/
nothing of the sorts in r, however.
vQ
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